Harry Melling lost too much weight.
The character of Dudley starts off as “the fat kid,” in Harry Potter’s world. He’s supposed to lose weight as the story progresses, but the actor who played him the movie, Harry Melling, lost too much weight. He went from a pudgy kid to a dapper young man. At one point filmmakers considered replacing the actor but opted for a fat suit instead. For Melling, it was just what his career needed to shed his famous role.