French heartthrob Olivier Martinez insists that there is a line he won't cross when it comes to shagging on the big screen. Of course, you might have a hard time believing that after seeing him and Diane Lane go at it behind Richard Gere's back in Unfaithful (opening nationwide Friday).

"I know it's not a French tradition, but I'm an actor who doesn't appear naked [in films]," the 36-year-old dreamboat confesses. "I don't play naked. I'm shy. Sometimes we're actors, but we're also human beings, and different personalities have different behaviors."

Ironically, Martinez had no problem with an Unfaithful scene that called for his character to seduce Lane's suburban housewife in the hallway of his apartment building — not to mention on top of a stall at a public restroom. "It's kind of cute. I like it," he says of the latter sequence. "They make love in public places because they're young and crazy. That's what she likes, that kind of craziness."

Despite all the attention focused on the movie's "mature" content, Martinez — who has thus far flown under the radar in such indies as Before Night Falls and The Horseman on the Roof — says Adrian Lyne's racy infidelity drama is "not only about sex. I think it's a real love story — a triangle."

And just in case you had any doubts, Martinez doesn't actually make love to Lane in the film. "I don't know why everybody comes to me [asking] about these love scenes — they're not real," he groans. "It's a lie. We are actors."