Drug-ban horse racing champion Frankie Dettori, former Steps star Claire Richards and 'X Factor' contestant Rylan Clark tonight entered the 'Celebrity Big Brother' house after weeks of speculation about the line-up.

They are joined in the latest series of the Channel 5 show by ex-'EastEnders' and 'Footballers Wives' actress Gillian Taylforth, model Paula Hamilton and former football star Neil "Razor" Ruddock.

frankie dettori

Horse racing champion Frankie Dettori

One absentee is comedian Jim Davidson who had been due to appear but was dropped after being arrested and questioned by detectives over allegations of sexual offences which he denies.

Clark was installed as favourite to win the show by bookmaker William Hill, with Dettori next.

claire richards

Former Steps star Claire Richardson

Also taking part in the new series are 'Neighbours' star Ryan Maloney - who has played Toadfish in the Australian soap since 1995 - as well as former 'Coronation Street' actor Sam Robertson and reality TV couple Heidi Montag and Spencer Pratt.

One-time 'Heartbeat' actress Tricia Penrose and glamour model Lacey Banghard complete the line-up.

rylan clark

X Factor reject Rylan Clark

There had been rumours that wild-child Hollywood actress Lindsay Lohan would be taking part but she was missing from the list of stars who rolled up to the studios at Elstree, Hertfordshire, to enter the house.

The contestants will spend the next few days holed up in the custom-built property in full glare of TV cameras with a winner emerging later this month if they can prove popular enough with viewers and their own housemates. The series is expected to last three weeks, with the first eviction due on Wednesday.

Dettori enters the house just weeks after he was given a six-month ban from his sport after a positive drugs test, which he said had left him feeling "ashamed and embarrassed".

lacey banghard

Sam Robertson and Lucy Banghard

"It doesn't matter what I took or how much - what I can say is it didn't make me ride any better or make my horse run any faster," the Italian-born showman said after the ban, which followed a positive test in Paris in September.

Hamilton found fame after starring in a VW ad campaign, but went on to have a problem with drink and drugs. She dated music and TV mogul Simon Cowell when she was in her teens.

paula hamilton

Paula Hamilton

Montag and Pratt may be largely unfamiliar to UK TV audiences but they featured in a string of US shows after first finding fame in MTV show 'The Hills'.

Show bosses were making life hard for some of the contestants with half due to be spending their time in a grotty basement area, while the others live in the more luxurious space in the house proper.

The series of 'Celebrity Big Brother' is the fourth to be screened by Channel 5 in the space of 18 months, after resurrecting the show which had been dumped by Channel 4.

heidi montag

Heidi Montag and Spencer Pratt

Casting bosses appear to have followed a similar format to the series this time last year which also roped in an 'X Factor' star just weeks after they were in the ITV talent show, Frankie Cocozza. That series similarly saw appearances from a former Eastender and a page three girl.

Ratings have been much reduced for the programme since it left Channel 4. The most recent 'CBB' series which finished in September and was won by Julian Clary drew an average of just 2.3 million viewers, the lowest audience yet.

It was almost three million down on the 5.2 million average audience for the first ever series in March 2001.

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  • Celebrity Big Brother - Launch Night

    BOREHAMWOOD, ENGLAND - JANUARY 03: Heidi Montag and Spencer Pratt enter the Celebrity Big Brother House at Elstree Studios on January 3, 2013 in Borehamwood, England. (Photo by Tim Whitby/Getty Images)

  • Celebrity Big Brother Launch - London

    Heidi Montag arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother Launch - London

    Heidi Montag arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • MTV's "The Hills Live: A Hollywood Ending" Finale - Arrivals

    HOLLYWOOD - JULY 13: Actor Spencer Pratt appear in costume across the street from MTV's 'The Hills' Live: A Hollywood Ending Finale at The Roosevelt Hotel on July 13, 2010 in Hollywood, California. (Photo by Frederick M. Brown/Getty Images)

  • Celebrity Big Brother Launch - London

    Heidi Montag arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother Launch - London

    Spencer Pratt arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother Launch - London

    Heidi Montag and Spencer Pratt are sent to the Big Brother Basement at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother Launch - London

    Heidi Montag and Spencer Pratt arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother Launch - London

    Brian Dowling, Heidi Montag and Spencer Pratt arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother Launch - London

    Heidi Montag and Spencer Pratt arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother Launch - London

    Heidi Montag and Spencer Pratt arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother Launch - London

    Claire Richards, Brian Dowling, Neil "Razor" Ruddock, Frankie Dettori and Rylan Clark at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother Launch - London

    Neil "Razor" Ruddock arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother Launch - London

    Neil "Razor" Ruddock arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother - Launch Night

    BOREHAMWOOD, ENGLAND - JANUARY 03: Neil Ruddock enters the Celebrity Big Brother House at Elstree Studios on January 3, 2013 in Borehamwood, England. (Photo by Tim Whitby/Getty Images)

  • Celebrity Big Brother - Launch Night

    BOREHAMWOOD, ENGLAND - JANUARY 03: Neil Ruddock enters the Celebrity Big Brother House at Elstree Studios on January 3, 2013 in Borehamwood, England. (Photo by Tim Whitby/Getty Images)

  • Celebrity Big Brother - Launch Night

    BOREHAMWOOD, ENGLAND - JANUARY 03: Neil Ruddock enters the Celebrity Big Brother House at Elstree Studios on January 3, 2013 in Borehamwood, England. (Photo by Tim Whitby/Getty Images)

  • Celebrity Big Brother Launch - London

    Claire Richards arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother - Launch Night

    BOREHAMWOOD, ENGLAND - JANUARY 03: Lacey Banghard enters the Celebrity Big Brother House at Elstree Studios on January 3, 2013 in Borehamwood, England. (Photo by Tim Whitby/Getty Images)

  • Celebrity Big Brother Launch - London

    Claire Richards arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother - Launch Night

    BOREHAMWOOD, ENGLAND - JANUARY 03: Claire Richards enters the Celebrity Big Brother House at Elstree Studios on January 3, 2013 in Borehamwood, England. (Photo by Tim Whitby/Getty Images)

  • Celebrity Big Brother Launch - London

    Claire Richards arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother - Launch Night

    BOREHAMWOOD, ENGLAND - JANUARY 03: Claire Richards enters the Celebrity Big Brother House at Elstree Studios on January 3, 2013 in Borehamwood, England. (Photo by Tim Whitby/Getty Images)

  • Celebrity Big Brother - Launch Night

    BOREHAMWOOD, ENGLAND - JANUARY 03: Rylan Clark enters the Celebrity Big Brother House at Elstree Studios on January 3, 2013 in Borehamwood, England. (Photo by Tim Whitby/Getty Images)

  • Celebrity Big Brother - Launch Night

    BOREHAMWOOD, ENGLAND - JANUARY 03: Frankie Dettori enters the Celebrity Big Brother House at Elstree Studios on January 3, 2013 in Borehamwood, England. (Photo by Tim Whitby/Getty Images)

  • Celebrity Big Brother - Launch Night

    BOREHAMWOOD, ENGLAND - JANUARY 03: Tricia Penrose enters the Celebrity Big Brother House at Elstree Studios on January 3, 2013 in Borehamwood, England. (Photo by Tim Whitby/Getty Images)

  • Celebrity Big Brother - Launch Night

    BOREHAMWOOD, ENGLAND - JANUARY 03: Tricia Penrose enters the Celebrity Big Brother House at Elstree Studios on January 3, 2013 in Borehamwood, England. (Photo by Tim Whitby/Getty Images)

  • Celebrity Big Brother Launch - London

    Claire Richards arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother Launch - London

    Sam Robertson arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother Launch - London

    Lacey Banghard, Brian Dowling and Sam Robertson arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother Launch - London

    Lacey Banghard arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother - Launch Night

    BOREHAMWOOD, ENGLAND - JANUARY 03: Lacey Banghard enters the Celebrity Big Brother House at Elstree Studios on January 3, 2013 in Borehamwood, England. (Photo by Tim Whitby/Getty Images)

  • Celebrity Big Brother Launch - London

    Lacey Banghard arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother Launch - London

    Lacey Banghard arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother Launch - London

    Sam Robertson arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother Launch - London

    Lacey Banghard and Sam Robertson arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother - Launch Night

    BOREHAMWOOD, ENGLAND - JANUARY 03: Samuel Robertson enters the Celebrity Big Brother House at Elstree Studios on January 3, 2013 in Borehamwood, England. (Photo by Tim Whitby/Getty Images)

  • Celebrity Big Brother Launch - London

    Sam Robertson and Lacey Banghard arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother - Launch Night

    BOREHAMWOOD, ENGLAND - JANUARY 03: Samuel Robertson and Lacey Banghard enter the Celebrity Big Brother House at Elstree Studios on January 3, 2013 in Borehamwood, England. (Photo by Tim Whitby/Getty Images)

  • Celebrity Big Brother Launch - London

    Gillian Taylforth arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother - Launch Night

    BOREHAMWOOD, ENGLAND - JANUARY 03: Gillian Taylforth enters the Celebrity Big Brother House at Elstree Studios on January 3, 2013 in Borehamwood, England. (Photo by Tim Whitby/Getty Images)

  • Celebrity Big Brother Launch - London

    Gillian Taylforth arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother Launch - London

    Brian Dowling and Gillian Tayforth arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother Launch - London

    Gillian Taylforth arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother - Launch Night

    BOREHAMWOOD, ENGLAND - JANUARY 03: Gillian Taylforth enters the Celebrity Big Brother House at Elstree Studios on January 3, 2013 in Borehamwood, England. (Photo by Tim Whitby/Getty Images)

  • Celebrity Big Brother - Launch Night

    BOREHAMWOOD, ENGLAND - JANUARY 03: Gillian Taylforth enters the Celebrity Big Brother House at Elstree Studios on January 3, 2013 in Borehamwood, England. (Photo by Tim Whitby/Getty Images)

  • Celebrity Big Brother Launch - London

    Ryan Maloney arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother Launch - London

    Ryan Maloney arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother Launch - London

    Ryan Maloney arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother Launch - London

    Tricia Penrose arriving at the launch of Celebrity Big Brother 2013, Elstree Studios, Borehamwood.

  • Celebrity Big Brother - Launch Night

    BOREHAMWOOD, ENGLAND - JANUARY 03: Tricia Penrose enters the Celebrity Big Brother House at Elstree Studios on January 3, 2013 in Borehamwood, England. (Photo by Tim Whitby/Getty Images)