James Corden Talks Losing Weight and Why Diets Don’t Work, Plus: His New Movie ‘Peter Rabbit 2: The Runaway’

James Corden is opening up to “Extra’s” Terri Seymour about his new movie “Peter Rabbit 2: The Runaway” and his weight-loss journey.

Corden is looking slimmer after joining WW, formerly Weight Watchers, back in January. “I’ve tried them all Terri,” he said of diet plans. “I’ve done every single one — shake in the morning, shake at night. I’ve done a lot.”

He’s down more than 20 lbs., and Terri asked him, “How are you feeling losing all the weight? You look amazing!”

James insisted, “Let’s not start using phrases like ‘all the weight’… it’s some of the weight… I feel great, it’s good, it’s going really well.”

The actor is also crediting WW for helping him finally shed some fat. “I don’t even like calling it a diet because that’s what I realized that I always did wrong was go on diets and you can’t go on a diet because if you go on a diet you are going to go off a diet, you’re going to eat everything you can.”

He added, “I’ve been trying to lose weight for like 20 years now and it’s the first thing I’ve ever done that genuinely works, the WW app, and the whole sort of wellness lifestyle.”

Sharing why he decided to do it now, he said, “Well, I decided to ‘do it now’ every year for about 25 years, so it’s just never, ever worked… So there’s no real change it’s just that this one’s working… Before, if I was on a diet, if I broke it, it would be broken forever, that would be it. I would have a bad day, one bad meal, and I’d be like, ‘Well, I’ve done it now, so I might as well go and eat all those sandwiches.’”

Now, he says, “When you have a slip up you go, ‘Okay, that happened, that doesn’t matter, what matters is I just carry on the road I was on before,’ then you go, ‘Oh, that’s what being healthy is,’ and I never really knew that… Calories in, calories out, try do some exercise as much as you can, know that you are going to have bad days, but don’t make it a bad month… You can always re-set yourself.”

Fans know that James is a cheeky guy, so of course he likes playing a naughty Peter Rabbit. “It’s great fun,” he says of the sequel he’s in. “It’s thrilling to do it, it really is… I enjoy playing those mischievous moments that are in him and, yes, in me. I love every second of jumping into this world.”

“It’s amazing how people have responded to the both of these films, particularly this second one… It’s really important to say that Will Gluck who directed and wrote both films, it is his world that he creates and just get to go and play in his sandbox a little bit.”

Terri watched the movie with her daughter Coco, telling James she woke up saying his catchphrase from the film, “Well, la-di-da.” James cracking up, quipped, “Well, la-di-da!”