The Sex and the City star revealed in his latest Parade column that he suffered two potentially serious injuries while rehearsing for Monday's season premiere.
"I had a few set backs during rehearsals. I tore my hamstring and a joint in my lower back and I wasn't sure if they would affect my performance, but I pushed on and realised nothing can stop me once I am on that dancefloor," Marini revealed.
The actor and his partner Peta Murgatroyd earned a 24 out of 30 from the Dancing with the Stars judges and survived the first elimination, but Marini apparently remains in significant pain.
Marini tweeted on Wednesday (September 26) night that he plans to see his doctor today (September 27) to have his injury assessed.
Dancing with the Stars: All-Stars continues Monday at 8/7c on ABC.
Watch Gilles Marini and Peta Murgatroyd's foxtrot below: