Blue Peter's Peter Duncan has replaced Mr Motivator on the BBC Tumble line up.
The new BBC One Strictly Come Dancing style series kicks off next month but was thrown into chaos when Mr Motivator - real name Derrick Evans - had to pull out.
It was revealed yesterday that he had dislocated his knee and required surgery, ruling him out of the live shows.
Fitness guru Mr Motivator said: “I’m devastated.”
But he added: “Good things sometimes fall apart but, from that, always remember we can only get stronger.”
The Daily Star on Sunday newspaper now reports that ex Blue Peter presenter Peter Duncan will replace him in the line up.
The 60-year-old will compete against the remaining celebrity line-up, who have been in training for the past six weeks.
They include world boxing champion Carl Froch, Girls Aloud star Sarah Harding and Loose Women host Andrea McLean.
Also joining the celebrity line-up are TOWIE star Lucy Mecklenburgh, BAFTA award winning ‘Wolfblood’ actor Bobby Lockwood, Sugababe Amelle Berrabah and Ian ‘H’ Watkins from Steps.
Tumble starts on August 9 on BBC One.