EastEnders actress Kim Medcalf is 2-1 favourite to win Comic Relief's second celebrity Fame Academy, with comedian Al Murray close behind.
Kim Medcalf performed in the EastEnders Christmas special
Radio 1 DJ Edith Bowman and comedians Adrian Edmondson and Jenny Eclair are among the celebrities set to compete in the charity singing show.
Hosted by Cat Deeley and Patrick Kielty, the competition launches on Saturday with a live final on 11 March.
Casualty actor Will Mellor won the first celebrity show in March 2003.
Other celebrities lined up to take part include TV presenters Nick Knowles and Reggie Yates.
Jon Culshaw of Dead Ringers fame and comedienne Gina Yashere, whose credits include The Lenny Henry Show, are also among the 13 contestants.
Coronation Street actress Debra Stephenson will take part, as will Christopher Colquhoun who played Simon Kaminski in Casualty and Monarch of the Glen's Dawn Steele.
Each of the contestants will face the public vote when they perform live every night from 2 March. The trio with the least votes face the prospect of eviction.
The celebrities will be living in Lambeth, south-east London
Three finalists will compete in a live finale during the seven-hour Comic Relief telethon on 11 March.
Comic Relief organiser Richard Curtis said: "There are hard times ahead for everyone, but I think we are going to make millions of pounds and change millions of lives."
One of the 13 celebrities will be evicted from the competition at the show's launch on 26 February, before the group even enters the academy.
Perrier Award-winning stand-up comedienne Jenny Eclair said: "I've already bought a chicken because I know I will be at home to cook it."
New Zealand-born actress Debra Stephenson, who plays Frankie Baldwin in Coronation Street, said: "I'd like to stay as long as I can. I would be upset if I didn't last the first day."
The resident students will be coached by Fame Academy veterans Carrie and David Grant, tutor Jeremy Milnes and choreographer Kevin Adams, in the new academy home at Lambeth College, south east London.
Judges include headmaster Richard Park and opera singer Lesley Garrett.