Four of Strictly Come Dancing's professional dancers are leaving the programme, the BBC confirmed.
One of them - Erin Boag - has been dancing with celebrity contestants on the show since it began in 2004.
A BBC spokeswoman said Boag, along with Flavia Cacace and Vincent Simone, were all leaving "to focus on their careers outside of Strictly and for professional reasons".
Former Strictly champion Aliona Vilani, who won in 2011 with McFly's Harry Judd, will not be returning for the next series either. She had not competed in the 2012 show due to injury, but no reason was given for her departure.
Boag, who has danced with Olympic medalist Colin Jackson and impressionist Rory Bremner, said: "After 10 wonderful years, and with a truly heavy heart, I have decided to decline the BBC's very kind offer to compete again in series 11, and have withdrawn from being a competitive dancer on Strictly Come Dancing.
"It's been so much fun making new friends, meeting wonderful people, and of course being partnered with such lovely celebrities year after year. I'm going to miss spending so much time with my amazing fellow professional dancers - it's true what they say, Strictly really is just like a great big family!
"It's been a very hard decision to make, but it's time for a change and to focus my attention on new challenges. That said, it's not necessarily farewell to Strictly, as I do hope to continue being a part of the show."
Boag said she would continue to dance with professional partner Anton du Beke, and told fans on her blog: "I'm certainly not hanging up my dancing shoes and retiring from the ballroom... far from it! I'm going to be doing more television work, choreography and teaching (news on that to follow!), and Anton and I will still be performing at shows and events across the country as usual.
Dance partners Cacace and Simone said they would take part in the show's Christmas special, also describing themselves as being "part of the family".
Cacace, who won last year's series with gymnast Louis Smith and is engaged to former Strictly contestant Jimi Mistry, said: "After an incredible and unforgettable 2012 on Strictly Come Dancing for both Vincent and I, we have decided we won't be partnering a celebrity on this year's show.
"However we look forward to continuing to perform on our favourite show and remain a part of the family including partnering a celebrity in the Christmas Special.
"We feel it's the right time to invest in our dancing knowledge and become better at what we do and keep providing our audiences and supporters with continued excitement through our dancing. Aside from hopefully performing on Strictly we have lots of new projects ahead which we are very much looking forward to working on.
"We have exciting times ahead with Vincent having his second child and me being newly engaged. We thank our supporters for always being there and hope that together with us they look forward to exciting times ahead."
The dancer was named joint Rear of the Year with Simone last week and said at the time that the show was "kind of in our blood". Simone described it as "such a hard job", adding: "It's probably the hardest thing we have ever done in our career."
The BBC said the pair would also perform tango routines on the 2013 series of Strictly, to be televised this autumn.
New dancers will be introduced to viewers when the next series begins.
Iveta Lukosiute, who stood in for Vilani on last year's Strictly and danced with presenter Johnny Ball, will be joining the show on a permanent basis, the BBC said. The Lithuanian-born dancer is currently world champion in 10 styles of ballroom dancing and has appeared on So You Think You Can Dance in the US.
British-born Emma Slater, who has appeared in hit film Mamma Mia! and sang on its soundtrack, is another newcomer.
She has also performed in the West End production of Dirty Dancing and made television appearances on ITV's Popstar to Operastar, and versions of Dancing With The Stars in India and the US.
She said of her new role: "I was absolutely thrilled to be asked to join Strictly, it's such an honour. However, one of the first things I thought of was my mum - she's going to be over the moon!"
Slovenian dancer Aljaz Skorjanec, who has represented his home country in world latin and ballroom dance championships for more than 10 years, described being asked to join Strictly as "the best news ever".
He added: "I can't wait to step into Strictly Come Dancing's ballroom."
The fourth new dancer is Janette Manrara, who is currently appearing in Burn the Floor in the West End and is a principal dancer on American television series Glee. She has also been a finalist on So You Think You Can Dance in the US.
She said it was a "dream come true" to join the series, and added: "I feel like a princess invited to a royal ball."