Ashton Kutcher Reveals He's Lost 12 Pounds From Marathon Training

In a new interview with Entertainment Tonight, the actor revealed that he's lost "about 12 pounds" amid his training for the 2022 TCS New York City Marathon.

“The biggest change physically has been the transfer of muscle mass from upper body to lower body. I’ve lost about 12 pounds," Kutcher said, sharing that his wife Mila Kunis has been "super supportive."

"Surrounding myself with a support system makes hard things much easier," he added, noting what he's learned about himself. "Setting a pace that you can sustain is not the same thing as working as hard as you can."

The "That '70s Show" alum is partnering up with Peloton for a 16-episode interview and marathon training series. The digital series will see Kutcher being coached by Peloton instructors as he interviews and trains with celebrity guests including Natalie Portman, Kim Kardashian, Jon Batiste, Kenny Chesney and more.

"We're ready to create some electricity in this place," Kutcher told ET.

"The conversations lean into what motivates the guests to move and explore their personal 'WHY?'" Peloton wrote of the series on its website.

As for his "why" and what motivates him, Kutcher -- who shares 7-year-old daughter Wyatt and 5-year-old son Dimitri with Kunis -- said, "My baseline ‘why’ comes down to leaving life better than what it was given to me. My daily motivator is my kids and family."

Kutcher has previously shared that he's running in the marathon to raise money for his non-profit, Thorn, which "build[s] technology to defend children from sexual abuse to eliminate child sex abuse material from the internet," according to a press release. Thorn, which was founded in 2012, is celebrating its 10th anniversary.

"The marathon itself is an elevating opportunity for the work that we have been doing for over a decade with Thorn," he told ET. "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," he added.

This comes a few weeks after it was revealed that Kutcher previously battled a rare autoimmune disorder.

While on an episode of "Running Wild with Bear Grylls: The Challenge" earlier this month, the "Vengeance" star told Grylls, "Like two years ago, I had this weird, super rare form of vasculitis, that like knocked out my vision, it knocked out my hearing, it knocked out like all my equilibrium. It took me like a year to build it all back up."

"You don't really appreciate it, until it's gone. Until you go, 'I don't know if I'm ever going to be able to see again, I don't know if I'm ever going to be able to hear again, I don't know if I’m ever going to be able to walk again,'" he added -- telling Grylls he's "lucky to be alive."

According to the Mayo Clinic, vasculitis is an inflammation of blood vessels which can lead to organ and tissue damage. Treatment includes taking a corticosteroid like prednisone or methotrexate to get the inflammation under control.

After he started making headlines with his health battle reveal, Kutcher took to Twitter to clarify the condition.

"Before there are a bunch of rumors/ chatter/whatever out there. Yes, I had a rare vasculitis episode 3yrs ago. (Autoimmune flair up)," he tweeted out. "I had some impairments hear, vision, balance issues right after."

"I fully recovered. All good. Moving on," he added. "See you at the 2022 NY Marathon w/Thorn."

The 2022 New York City Marathon takes place on Sunday, November 6.