Bruce Willis "kissed like a camel", according to actress Cybill Shepherd.
Cybill, who starred with the Die Hard actor in Moonlighting, said his smooching technique only improved when he met his ex-wife Demi Moore.
Cybill told the New York Post newspaper: "Yeah, when we first started out, hewould just kiss like a big old camel.
"And then he got involved with Demi Moore, and she taught him some."
Meanwhile, Bruce has threatened to "beat up" anybody who mocks his baldness.
The actor has refused to wear a wig for his role as cop John McClane in the fourth Die Hard movie, Live Free or Die Hard, because he wants to show the character has aged.
Bruce, 51, has issued a stern warning to anyone who ridicules his lack of locks, saying: "I'm a man and I will beat up anybody who tries to tell me that I am not a man just because my hair is thinning."
