Shooting Stars comic Reeves and 2010 Let's Dance winner Hound will give their verdicts on five celebrity acts.
Reality TV stars Amy Childs and Harry Derbidge, as well as comic Miles Jupp and Eddie 'The Eagle' Edwards, will battle it out in episode two for a place in the final.
Brit nominee Ed Sheeran and 2008 X Factor winner Alexandra Burke will give guest performances during the show.
Outnumbered star Tyger Drew-Honey and 2011 I'm a Celebrity contestant Fatima Whitbread are among the stars to appear sometime later in the series.
For the first show, which airs this weekend, Graham Norton, Keith Lemon and Inbetweeners comic Greg Davies will be judges, with JLS and Jessie J as special guests.
Meanwhile, the first week's competitors will be Shooting Stars duo Angelos Epithemiou and Ulrika Jonsson, comic Terry Alderton, EastEnders stars Tameka Empson and Laurie Brett, and veteran DJs Tony Blackburn and David Hamilton.
Hosted by Alex Jones and Steve Jones, Let's Dance for Sport Relief kicks off on Saturday, February 25 at 7.10pm on BBC One.
Watch Celebrity Juice's Rufus Hound performing on Let's Dance below: