Winkler appeared on the Dec. 24 episode of IMO with Michelle Obama & Craig Robinson, where he talked about his milestone birthday, which took place Oct. 30. The Happy Days star said that Obama, 61, told him that he should celebrate his birthday for the whole year.
"Eighty is one of those that's where you deserve a year of celebration," she said. Winkler joked, "I deserve new knees."
Obama noted that Winkler is "moving around pretty well" for his age. He said, "I get out of bed and I go make a cup of coffee. And then I have to go back to the bed and invite my knees to come with me. They're still lounging."
The hosts asked how he's feeling outside his knees. "I'm very grateful," he said. "You know, people keep asking me am I gonna retire. Or 'Have you retired?' And I think that is like the furthest thing from my imagination. I will retire when I am not able to do again, more." he shared.
"You know, I just, I think that it is deadly," the actor said of retirement.
He said he needs to work, which he does "a lot," noting he has "several jobs." That includes his 2025 series Hazardous History with Henry Winkler, which premiered on The History Channel this year and has been renewed for a second season.
He also continues to write books, and this fall released his 40th book, Detective Duck: The Mystery at Emerald Pond, which he wrote with his writing partner Lynn Oliver.
Later in the podcast, Winkler praised therapy for helping him make it this far. He said that when he started therapy about ten years ago, he was "completely discombobulated." He compared himself to swiss cheese and said therapy helped him fill the holes inside him.
In 2018, he joined the cast of Barry as acting coach Gene Cousineau, a role which finally won him an Emmy that year, at age 72. He said of therapy, "I don't know that I could have played Gene Cousineau without going through that process." He said the biggest thing he learned in therapy was to listen to his "instinct."
"Your mind, as educated or not as you are, your mind only knows a little. Your tummy knows everything,"
he said.
On Instagram on Dec. 28, Winkler showed how he's not slowing down, even with his knee problems. He posted a video of himself ziplining and was all smiles as he reached the end of the course. He wrote in the caption, "Still zipping at 80."
Back in August, Winkler opened up to PEOPLE about his longtime friendship with Ron Howard, his Happy Days costar. "Every time I see him, it's like there is no time lost. We just pick up right as if I saw him yesterday," he said.
Howard, 71, said of their bond, "We just clicked as acting partners. We became great friends and he was -- and is -- kind of like a big brother to me. Donnie Most, Anson Williams, Henry Winkler and I have sort of an ongoing text thread so there's just a kind of running dialogue updating what's going on."