Actress Helena Bonham Carter has let slip a secret on the final chapter in the Harry Potter series. Cater, who plays Bellatrix Lestrange in the latest movie Harry Potter and the Order of the Phoenix, only took the part after J.K. Rowling said her character has a big part to play in the final book. She tells London radio station Heart FM, "When I was offered Bellatrix I realised it wasn't a very big part. "One day J.K. sent me a message to say that I was going to be very significant in the seventh book so that was a bit of a carrot… "I am a big fan of Harry Potter anyway, the books, the genre, the whole world of Harry really… so I said yes."