“The Artist” actor Jean Dujardin was serenaded by DJ Sunnery James at Bagatelle on St. Barts on Wednesday night. Dujardin was at the holiday hot spot with a friend, and was dressed so casually, in jeans and a T-shirt, that fellow diners didn’t recognize him. But James, on St. Barts with his model wife, Doutzen Kroes, who was shooting for Victoria’s Secret, spotted the Oscar winner and hopped behind the DJ booth for an impromptu spin session, playing some tunes for the handsome French star.