The singer looked almost unrecognisable as she stopped by ITV’s ‘Lorraine’ for a chat with the Scottish TV presenter.
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Hannah Spearritt's new look
Having undergone a punky makeover for her new role in 'Casualty', Hannah looked in contrast from her days as a perky blonde popstar, with her locks dyed pink and purple, and a new nose ring.
She is set to play troubled Mercedes Christie on the BBC medical drama, making her debut this Saturday.
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Hannah as she appeared last year
Speaking about her role, Hannah told Lorraine: "I was apprehensive, because going into such an established show, there was that new girl thing going on.
"[But] there's always a lot of new characters coming in. I felt really welcomed. It's one of the nicest sets I've ever worked on."
The star reunited with her S Club bandmates last year for an arena tour, and while new music from the band was rumoured, it has since failed to materialise.
However, the couple called time on their relationship for a second time in November.
S Club 7: Where Are They Now?
(01 of14)
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As soon as the band made it into the charts, Rachel Stevens became a permanent feature on FHM's annual Sexiest Women lists... (credit:PA)
(02 of14)
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... And in 2014, she's still in them.Rachel was recently named FHM's Sexiest Woman Of All Time. She's still in showbiz and in 2013, she appeared as a guest mentor on the New Zealand version of 'The X Factor'. Rachel starred in the 2009 series of 'Strictly Come Dancing' and has two children. (credit:Getty Images)
(03 of14)
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Hannah Spearritt had already appeared on 'Blue Peter' and 'The National Lottery Show' when she auditioned for S Club 7 after seeing a magazine advert in 1998. (credit:PA)
(04 of14)
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Now, she's more well-known as an actress and has starred in TV dramas 'Primeval' and 'Marple'. (credit:ExcaliburMcElhinney/WENN)
(05 of14)
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Paul Cattermole was the first singer to leave S Club 7 in 2002 after deciding to pursue a rock music career instead. (credit:PA)
(06 of14)
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After leaving the band, Paul split from Hannah, who he had dated for six years. In 2008, he reunited with Jo O'Meara and Bradley McIntosh. The trio performed a number of small gigs before disbanding again. (credit:PA)
(07 of14)
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Bradley McIntosh was just 18 when he was busted for drug use along with the other male members of S Club 7 in 2001. (credit:PA)
(08 of14)
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After failing to achieve chart success with band Upper Street, Bradley decided to go it alone and currently works as a singer and producer. (credit:Getty Images)
(09 of14)
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Dancer Tina Barrett was originally supposed to be in Mis-Teeq, however she chose to join S Club 7 after making it through the grueling audition process. (credit:PA)
(10 of14)
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Tina is still trying to carve a successful solo career and her next single 'Woman' is due for release later this year. (credit:Getty Images)
(11 of14)
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Jo O'Meara started out in a hip-hop group before becoming the lead vocalist in S Club. (credit:PA)
(12 of14)
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After the band's split, it was thought Jo would pursue a solo career, however, back problems meant she was unable to perform. Jo then appeared on 'Celebrity Big Brother' in 2007, where she became embroiled in a racism row. She now performs with band The Popes. (credit:PA)
(13 of14)
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Jon Lee was one of the only S Club 7 members who was new to showbiz when he joined the band. (credit:PA)
(14 of14)
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Nowadays Jon spends a lot more time in the gym. When he's not pumping iron, Jon appears on the West End stage and has starred in productions including 'Les Miserables' and 'Jersey Boys'. (credit:Instagram)