Sacha Baron Cohen sneaked onto the courtroom set of Medium yesterday in the guise of Bruno, the flamboyant Austrian fashion reporter that's the focus of his new film. A show insider said, "No one had a clue it was Sacha playing Bruno. It's amazing he was able to infiltrate the set and pull this off." He's also appeared in Milan, Paris and at a Prop. 8 rally last week. [EW]