The above image is from a 1952 film called Bela Lugosi Meets a Brooklyn Gorilla - and no, that isn't Dean Martin and Jerry Lewis but a very close approximation (in looks if not in talent): Duke Mitchell and Sammy Petrillo.
Petrillo, who looked and acted exactly like Jerry Lewis, died today at age 74.
I've seen Brooklyn Gorilla, and it's about as bad as you might expect. However, Petrillo did such a good Jerry Lewis impression that it's hard not to like. Here's a clip.
As you might have guessed, Mitchell and Petrillo didn't get very far with their act thanks to the constant threat of litigation from Jerry Lewis. However Petrillo did make another major contribution to pop culture - his sitcom treatment "My Daddy was a Monster" was the basis for The Munsters.