Michael J. Fox Gives Charlie Sheen the Thumbs-Up (Video)

Former "Spin City" star says his replacement "did a great job," and that he's not as crazy as some other celebrities

It's good that Michael J. Fox wasn't tapped to participate in Comedy Central's upcoming roast of Charlie Sheen — he doesn't seem to have anything negative to say about the guy.

Fox sang the praises of the former "Two and a Half Men" star on Thursday night's "Late Show," telling David Letterman that Sheen "did a great job" replacing him on "Spin City."

"It was especially good because he worked and I got paid," said Fox, who remained a producer on the show after he left due to his Parkinson's disease.

Asked by Letterman about Sheen's recent shenanigans, Fox replied, "Well, he says he's doing okay, so who is it for me to say he's not?"

Fox added that Sheen's antics are relatively tame, at least compared to those of his former "Back to the Future" co-star many years ago.

"Any level of craziness to me has not risen to the level of Crispin Glover almost kicking you in the head," Fox quipped.

Watch Fox talk Sheen on Letterman in the video.