LOS ANGELES (Reuters) - Jean Dujardin won the best actor Oscar on Sunday for silent film "The Artist," becoming the first Frenchman to win the coveted accolade and beating out Hollywood frontrunners George Clooney and Brad Pitt. Dujardin was largely unknown outside of France until "The Artist" became the toast of film festivals and started racking up awards last year for his moving, virtually silent portrayal of a dashing actor struggling with Hollywood's transition from silent to talking pictures. Clearly overwhelmed at his win a beaming Dujardin took to the stage punching the air. ...