Actors James and Oliver Phelps are twins in real life, just like the characters they play, Fred and George Weasley. They are not, however, real redheads. They both had to dye their hair for the movies. Oliver even tweeted a picture of himself getting his hair dyed red for the last time when shooting for Deathly Hallows. That's a pretty significant event when you consider that the twins have had to do this for ten years!