Ashton Kutcher Details 12-Lb. Weight Loss, Mila Kunis' Support While Training for NYC Marathon

Ashton Kutcher is detailing his physical transformation while training for the 2022 New York City Marathon.

The 44-year-old actor recently spoke to Entertainment Tonight and revealed that he's dropped 12 lbs. while preparing for the race, which is scheduled for November 6.

"The biggest change physically has been the transfer of muscle mass from upper body to lower body. I've lost about 12 lbs.," he told the outlet, adding that "my wife [Mila Kunis] has been super supportive."

Kutcher said dedicating himself to the process has taught him that "surrounding myself with a support system makes hard things much easier. Setting a pace that you can sustain is not the same thing as working as hard as you can."

Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.

The That 70s Show actor explained that his family — Kunis, 38, and their two kids, son Dimitri Portwood, 5, and daughter Wyatt Isabelle, 7 — is his motivation to cross the finish line this fall.

"My baseline 'why' comes down to leaving life better than what it was given to me. My daily motivator is my kids and family," he told ET.

Kutcher is also participating in the upcoming marathon to raise money and awareness for Thorn, which works to build technology to defend children from sexual abuse and eliminate child sexual abuse material from the internet.

"The marathon itself is an elevating opportunity for the work that we have been doing for over a decade with Thorn," he said. "A chance to show the folks that have been working so hard to make our vision reality, that I'm in it with them and willing to go to the last mile."

"Every move we make is in consideration of creating scalable outcomes that help children have lives where they can just be kids," Kutcher added.