Ashton Kutcher Says He Almost Named a South Pole Mountain After Wife Mila Kunis: 'It Was Wild'

Ashton Kutcher is moving mountains for his wife Mila Kunis — well, at least trying to name one after her!

The 45-year-old actor talked about the romantic gesture while promoting his new film, Your Place or Mine, on Monday's episode of The Late Late Show with James Corden.

Discussing a trip to the South Pole he once took to help with an autoimmune condition, Kutcher said he met a man who asked if he wanted to climb a mountain, to which he agreed.

"We get to the top and he said, 'You're the first person that has ever climbed this mountain. You get to name it,' " he recalled to host James Corden. "I was like, 'Okay really? It's Mount Mila.' And he says 'No, no, it's bad luck to name it after another person, so don't do that.' "

Kutcher shifted gears and named it "Awesome" in Russian. Kunis, 39, was born in the Ukraine and grew up speaking Russian.

"So I got to name a mountain while I was there," the entrepreneur added. "It was wild."

Expanding on what brought him to Antarctica in the first place, Kutcher further discussed his health.

"I had a weird autoimmune disorder three years ago," he said. "So last year, I was like, 'I am just going to push myself to the end of my physical capacity in every form.' "

"I went to the South Pole, I ran a marathon, I went Running Wild with Bear Grylls," the former model continued to Corden, 44, of his personal mental and physical journey. "I was just going to push it as far as I can just to get the self-confidence that I'm fully back, which I am."

And after a long break from romantic comedies, Kutcher currently has a No. 1 movie on Netflix with Reese Witherspoon, Your Place or Mine.

"Her character lives in Los Angeles, has a kid, and I'm in New York," he shared of the film about two long-distance best friends who decide to swap homes. "By switching lives, they realize they maybe should have been together all along."

The audience, along with fellow guests Quinta Brunson and Cara Delevingne, clapped after a clip was played of Kutcher and Witherspoon's flirty characters on a video call.

Earlier this month, Kutcher made headlines following the film's premiere when his wife teasingly commented on how "awkward" he looked on the carpet with her pal Witherspoon — a little hunched over with his hands in his pocket. He later explained it was on purpose.

"Here's the thing: If I put my arm around her, and was like all friendly with her, I'd be having an affair with her," Kutcher said during a guest spot on the Chicks in the Office podcast.

He added, "Like, the rumor would be that I'm having an affair with her."

Speaking with PEOPLE about Your Place or Mine in December 2022, Kutcher said signing up for the film was an "easy" decision, as he "finally got the opportunity" to collaborate with Witherspoon, 46, and writer/director Aline Brosh McKenna, "two women I have wanted to work with for years."

The film is co-produced by McKenna, 55, plus Jason Bateman, Michael Costigan, Lauren Neustadter and Witherspoon, the latter of whom Kutcher said working with "is like hanging out with a best friend."

"We just had fun!" he raved of their time on set. "I can talk to Reese about anything — acting, business, kids, media, football. She's always game."

And Witherspoon couldn't have agreed more, telling PEOPLE of Kutcher, "I think he's so funny. We have a very similar sense of humor and timing."

Your Place or Mine is currently streaming on Netflix.