"A Star Is Born"(1937)

Janet Gaynor (pictured) has just won the best actress Oscar. So who should stumble in and interrupt her acceptance speech but her drunk husband, Fredric March? He's a past Oscar winner himself (March as well as his character), so he's presumably entitled to dismiss the statuette as "that little piece of bric-a-brac." What he's not entitled to do is slap Gaynor, which he also does, albeit inadvertently.