Simon Pegg has revealed he could not resist cheating on his Mission Impossible diet.

He told how he and co-star Rebecca Ferguson, who plays Ilsa, cheated, but that A-lister Tom Cruise did not once "break his diet".

For his role in the upcoming blockbuster titled Rogue Nation, Pegg had a gruelling training schedule and diet.

"We ate very well, and we had these 'cooler bags', they were called," he explained.

"You'd pick them up in the morning and they had your breakfast, lunch and dinner in them, beautifully prepared, really nutritionally exact meals, so that we could be in tip-top shape.

"I was supposed to be a secret agent, so we were in great shape."

"Tom is on it - he will not break - but Rebecca and I would be like, 'Did you eat your chocolate on the pillow at the hotel last night?' 'Yeah, me too'."

Cruise also did his own stunts for the movie, and Pegg said the Hollywood star "relishes the challenge".

"I think he likes to be stretched," he said.

"There's a reason why he is where he is and why he is who he is, because he has this dynamic kind of thrust."

He went on to joke: "I worry in a way, like if we do Mission: Impossible 6, he's going to have to go into space, because he can't get any higher."

Mission: Impossible - Rogue Nation is due for UK release on July 30.