James of "The Godfather"

CAAN

This actor played Sonny Corleone and also starred in a 1981 comedy about a man who switches bodies with his daughter.

The clue refers to James Caan, the actor famous for playing Sonny Corleone in The Godfather film series. Since the first name "James" is given, the answer is simply his last name, "CAAN." It’s a straightforward reference where the movie title directly points to the actor’s identity.