James Franco has recorded a song with Motown legend Smokey Robinson after a chance encounter on a plane. “He asked me to do it, and so I did it,” Robinson told us at Monday’s Angel Ball at Cipriani Wall Street of his duet with Franco and his band, Daddy, on the song “Crime.” “It’s as simple as that. There’s no deep dark secret.” Robinson said they met on a plane two years ago and became friends — “James is my brother.” Robinson was recently in New York for a preview of Berry Gordy’s 2013 Broadway musical “Motown.” “It’s going to be absolutely awesome,” he said. Other guests at Denise Rich’s glam ball, which raised $3.7 million to fight cancer, included Gerard Butler, who danced the night away with a group of models, Kim Kardashian and Kanye West, Bar Refaeli, Loren Ridinger, Clive Davis, Stephen Baldwin, Nelly, Eva Cavalli and Joan Collins. Star Jones emceed an auction, and joked, “Denise asked me to do this because I know all the rich people in the room,” and persuaded Stewart Rahr to donate $250,000 to the cause.