Sophie Turner spent a year training for Tomb Raider and discovered back issue in the process

Sophie Turner has a "perpetual back problem".

The 29-year-old actress - who has daughters Willa, five, and Delphine, three, with her former husband Joe Jonas - discovered a recurring health issue while undergoing gruelling training for her role as adventurer Lara Croft in the upcoming Tomb Raider TV series.

Speaking on The Julia Cunningham Show, she said: "We've been doing eight hours a day, five days a week since February of last year, of training. Yeah, so it's been a lot.

"I've learned I have a perpetual back problem, but I also realized that it's much easier to kind of build muscle if you've ever worked out before in your life, which I never had, so it has taken me months and months and months to get into good shape. That's what I've learned."

Sophie is best known for her role as Sansa Stark in Game of Thrones but she insisted her years on the fantasy drama series didn't help prepare her for Tomb Raider because she was never involved in any action scenes.

Asked if Game of Thrones had helped her at all, she replied: "No, I was the cool queen who, like, didn't have to do that. I also just kind of was the one that got beat up, not the one doing the beating. So, it's quite nice to learn how to throw a punch and not just take it."