Nope, he's just that good.
John Mahoney, who played Martin Crane on the long-running sitcom hit "Frasier," is indeed quite a gifted actor with an incredibly broad resume. The limp - ostensibly from a bullet wound he got while working as a police officer - is put on for the role.
Indeed, in an interview with the BBC he said that even after doing the role for 11 seasons, he'd occasionally forget.
"Every once in a while I do; sometimes I forget to use my cane, especially if you are doing a scene and sitting down. Sometimes I jump up and walk away; the audience loves it, they love screw ups."
Though he's best known for his TV work, he's also a Tony Award-winning stage actor and established character actor in film.
But he keeps going back to TV, most recently joining the cast of the acclaimed HBO series "In Treatment."