In yet another interview, this time with Rotten Tomatoes, Helena Bonham Carter spoke about Bellatrix Lestrange and what happens to her at the end of Deathly Hallows.  Spoilers abond!

“I’m mostly in [Deathly Hallows: Part 2],” she told RT. “But it was fun. I died on my last day, which was really weird — to actually be [killed] on my last day. Molly Weasley – Julie Walters – kills me.”

And it’ll be quite the moment, she explained. “I do get a good death scene,” she told us. “It was really exhausting. As usual! [I’m] duelling, with a wand, on a table. I fell right off. I was clever enough to say, ‘If you’re going to ask me to duel, backwards, can we put a stuntman at the end?’ They said, ‘Ah, you won’t need one.’ And what did I do? Walked straight off. You’d think with 70 people looking at you, one of them would go, ‘Er, could you stop?!’ No! They loved it. I nearly killed myself — on the day that I died.”

For Bonham-Carter, bringing Bellatrix to an end was an emotional experience given her investment in the creation of the character as she appears in the films. “Bellatrix wasn’t on the page,” she explained. “I did think, What can I do to make this interesting? She was just written as tall and gaunt, but I knew there was something I got attracted to — playing arrested development. You know, children. Bellatrix is another child — stuck and totally anarchic.”