Wilson dropped out of the DreamWorks movie after and apparent suicide attempt last month.
"Tropic Thunder" stars Ben Stiller, Jack Black, Robert downey Jr., Nick Nolte, Bill Hader and Steve Coogan.
McConaughey, 37, has an uncredited cameo in the movie, his publicist, Nicole Perez, said Wednesday.
"Tropic Thunder" is about a group of actors who gather on a remote island to shoot a big-budget war movie and are forced to become the soldiers they are playing. (AP)