"When I was 15, I went to play the piano for this white guy's Christmas party" in Texas, Jamie Foxx says. But when he and a friend showed up at the client's mansion, the host stopped them, saying, "I can't have two n— in my house at one time."

Foxx says he was forced to send his friend home, even though his pal had given him a lift to the party.

The "Ray" star was so rankled by the experience that, once he hit it big in Hollywood, he instituted a similar quota system.

Whenever two white guys came to party at his pad, Foxx tells Oprah Winfrey in December's O, he'd tell them, "You all will have to make a decision between you two."

Foxx adds that his friends "had to counsel me and say, 'Don't fall into that same trap.' "

The Oscar winner later changed his entrance policy — though, he points out, he never set a limit on white women.