Ashton Kutcher has shed 12 pounds training for marathon

Ashton Kutcher has shed 12 pounds (5.5 kilograms) training for the New York City Marathon.

The Vengeance actor is preparing to run the race on 6 November, and in an interview for Entertainment Tonight, he revealed that he has lost quite a lot of weight in the process.

"The biggest change physically has been the transfer of muscle mass from (the) upper body to lower body. I've lost about 12 pounds," he revealed.

Ashton went on to note that his plan is to set a pace that he can sustain in the race, and shared that his wife Mila Kunis has been "super supportive".

The 44-year-old is partnering with bosses at indoor cycling company Peloton to train for the marathon and is running to raise money and awareness for Thorn, his nonprofit dedicated to defending children from online sexual abuse.

The collaboration centres on an interview series, Our Future Selves with Ashton Kutcher, where Ashton and special guests, like Natalie Portman, Chris Paul, and Kenny Chesney, will explore their "why" - the reason why they get up and do what they do every day.