Tom & Jerry were nominated for an Academy Award for 1951's "Jerry's Cousin". Unfortunately, they lost out to UPA's Gerald McBoing-Boing.
Jerry sends for his street tough cousin, Muscles (voiced by Paul Frees), to help him when Tom is getting a little too hot under the collar. In effect, Bill Hanna & Joe Barbera had introduced MGM's answer to Mighty Mouse, except that Muscles doesn't seem to ever be happy. Cats fear him, and soon, Tom learns that important lesson.
Frees' only other work for MGM was narrating Tex Avery's "_______ of Tomorrow" series, insofar as I know.