Doctor Who star Matt Smith has regenerated - the actor has bulked up his physique after hitting the gym.
Matt, 30, whose alter-ego returns on BBC1 this weekend with The Bells Of Saint John, said that regular workouts had made him happier.
"Since I've been back in London, I've been going to the gym three times a week," he told the Radio Times.
"It makes me feel much better about my life, I have to say. It's just good for my mind."
Asked whether he was inspired by Hollywood actor Ryan Gosling, the director of his forthcoming film How To Catch A Monster, he laughed: "I haven't seen his abs yet."
Co-star Jenna-Louise Coleman told the magazine that Matt was the biggest diva out of the pair, saying: "He demands sweets at certain times of the day and Diet Coke in his trailer."
Matt defended the sci-fi show from criticism that there was not enough to mark its 50th anniversary year.
"There's only so many you can make each year without compromising the quality. It will be everything that it needs to be, the anniversary. And in November there will be a right old party," he said.
Asked how long he would go on in the role, he said "Forever!... I'm attached to the show for the next year and I take it year by year. I think that's the only way you can take it."