Ashton Kutcher is losing his hair.

The 40-year-old actor has admitted that he has been battling hair loss for over a decade and had been taking medication to stave off the problem, but after he stopped the treatment three years ago, he has been forced to become a ''baseball cap guy'' as he loses his luscious locks.

During an appearance on 'Conan' on Monday (04.06.18) night, the show's host Conan O'Brien told him: ''You always look good. You've got good hair.''

To which the 'The Ranch' actor - who has three-year-old Wyatt and 18-month-old Dimitri with his wife Mila Kunis - said: ''I'm going a little bit, though. I'm losing it. If I really get up in there, guys, it's starting to disappear.''

Ashton then went on to explain how he discovered his hair loss at the age of 25, and had been taking pills to prolong the inevitable until a few years ago when it came to starting a family with former 'That 70s Show' co-star Mila.

He said: ''When I was, like, 25, I noticed it was starting to go. I went to the hair-guy doctor, and he put me on this medication called Avodart. Have you ever heard of this stuff?

''I didn't know: Is it safe to take? So, I stopped taking the stuff about three years ago and now I'm experiencing the hair loss. It's starting to go. I'm a baseball cap guy, so I think I'm OK. I've established myself as a baseball cap-wearing individual. When it does go, you're not going to know that it's gone, because I'm just going to have a ball cap on.''

This isn't the first time Ashton has detailed his baldness battle, as he previously admitted he was ''comfortable'' with his hair loss now that he's a married father.

He said: ''I've actually become comfortable with it. I'm just good with it. I've got kids now.''