When Harry Potter 20th Anniversary: Return to Hogwarts premiered on HBO Max on New Year's Day, the reunion special confused one of its biggest stars with another actress who has a similar name. During a segment in which Emma Watson, who played Hermione Granger in the movies, talks about falling in love with the Harry Potter books as a child, a photo of a young Emma Roberts was shown on screen, BuzzFeed reports. Viewers pointed out the error (Roberts had posted the photo of herself as a youngster to social media back in 2012) and producers quickly fixed the mistake, Entertainment Weekly reports. Watson's wasn't the only slight: producers also mixed up the names of James and Oliver Phelps, the real-life twins who play twins Fred and George Weasley in the movies. (More Harry Potter stories.)