Simon Pegg has joked his combat training ahead of Mission: Impossible - Ghost Protocol prepared him for "running down some steps".

The British funnyman stars in the fourth film in the action franchise, which sees Tom Cruise reprise his role as daredevil Ethan Hunt. Simon plays fellow IMF agent Benji Dunn, a technical expert who joins the field team.

Simon underwent a training regime alongside the rest of the cast to ensure he could convincingly portray a field agent. However, the star has joked the schedule was a bit of a wasted one.

"I did fight training and weapons training. It's great to be paid to work out," he quipped in an interview with BBC Breakfast. "I ran down some steps. It sounds easy but I had to do it 15 times. They dropped [the film reel on the way to editing] and I had to do it again. I couldn't walk.

"Run down steps? Now that's hard!"

Simon was amazed by Tom's commitment to the high-octane film. The Hollywood star also co-produced the movie, which saw him scale the Burj Khalifa tower in Dubai the tallest building in the world.

Simon respects Tom's decision for not using a stunt double, although he'd never choose to do it himself.

"It's like being in an aeroplane. He absolutely did it. It's Tom Cruise. You should see it in IMAX you'll throw up," he smiled. "It is 100 per cent him. Tom can insist. It's important to him that people know he did it.

"We were watching it live that's scarier."

Simon also recently worked with Daniel Craig on The Adventures of Tintin. The 41-year-old star was pleasantly surprised by the James Bond actor when they first met.

"Danny, when we all met him, we thought he was going to be all tough and really difficult, but he is a big giggler and a very silly man," he revealed.