Henry Winkler finally started therapy aged 70 to rid himself of "rancid garbage" in his mind.

The Happy Days legend, now 80, started speaking to a professional around a decade ago after realising he was struggling to think rationally.

Admitting he felt like he was "treading water", he told In Depth With Graham Bensinger: "About 10 years ago, maybe 12 years ago, I was pretty good at either figuring things out or making it or smoothing things out in my mind or rationalising.

"And I just couldn't do it anymore."

His wife Stacey Weitzman previously admitted she wasn't being "let in", and the actor confessed he "didn't let anybody in".

He added: "I was not being able to just [say], 'Oh, well, OK, I'll move that aside and I'll just move forward'.

"I needed to now empty myself out of all of the rancid garbage I had allowed to infiltrate."

Henry noted that he has noted a huge difference in his mental health simply by listening and not having to give his point of view "unless it's asked for".

He added: "I was out of balance. I was out of my f****** mind."

Henry, who admitted he's "getting there" nowadays, compared him Swiss cheese.

He explained: "I was Swiss cheese. I was filled with holes. And I had to constantly be anxious about stepping in one of those holes. And my job is to become a chunk of cheddar, not a hole in sight."

Henry shot to stardom as Arthur 'Fonzie' Fonzarelli on Happy Days, the hit TV show, between 1974 and 1984, and he previously admitted he struggled to cope with his new reality when the series ended.

During an appearance on the Where Everybody Knows Your Name podcast, he explained: "After Happy Days finished, I'm sitting in my office [and] all I'm getting are Fonzi-like [offers]. I have no idea, 'Am I ever going to do anything that is as powerful?' And I went dark. I went dark."

Henry admitted to feeling lost and unsure of his future when the show ended. The actor explained that his career ground to a halt for "eight or nine years" after Happy Days.

The Hollywood star said: "The greatest thing you learn is to pivot.

"You're going on a way and you're thinking, 'Oh, I've got to stay. I can't do anything else. I don't want to do anything else.' You have to learn to pivot. And when you pivot, the universe opens up and all of this generous stardust falls on you."