In a new interview, Helena Bonham Carter talks about her fight scene in Harry Potter and the Deathly Hallows: Part II. If you don’t want any spoilers for the book, I suggest you stop reading now:

The actress, who plays evil witch Bellatrix Lesrange in the film series, fought against Julie Walters’ character Molly Weasley so hard in their pivotal final moments, they were both aching afterward. She said: “You should warm up before sword fighting, that’s what Julie and I found out when we were duelling with each other. We were crippled after that scene! Duelling going backward on a table is tricky, without falling off. Which, of course, I did!”

The duel was a source of amusement for the film’s cast and crew too, especially because they were watching the two characters go from being friends to mortal enemies every time the cameras rolled. Mark Williams, who plays Arthur Weasley, told Empire magazine: “They could’ve sold tickets for filming that scene. They were chatting one minute and cutting each other to bits the next. It was brilliant!”

This is a snippet from her interview in Empire magazine, make sure to pick up your issue today!