Just saw a tweet from @officialbtf (Burn The Floor) - it links to their Facebook, where it says:
Brian Fortuna has announced tonight that he will not return to Strictly Come Dancing on BBC TV this season. He has loves the experience and his fans, however he wants to give 100% to his upcoming role in Burn the Floor, with Ali at the Shaftesbury Theatre, London. Ali starts rehearsals on Friday and Brian will join her on Sunday for his first session with Jason Gilkison.
Somehow, I don't think he'll be the only one - if I was Brian, Darren, Lilia, Matthew or Ian, i would be highly insulted that I wasn't being asked back to compete; somehow the offer of a professional dance group seems more like a consolation prize (or a PR idea) so that the Beeb can say "Well, we offered them a place on this years show, and it was their choice to turn it down!
The Beeb are obviously not going to be happy til they've run this show into the ground....