'Happy Days' star Anson Williams shares shirtless selfie at 77 with a defiant message about aging

Anson Williams is feeling better than ever at 77.

The actor, best known for playing Potsie Weber on the beloved sitcom "Happy Days," shared a shirtless selfie Saturday while celebrating his health, creativity and continued career.

"My yearly reminder to every Boomer: NEVER let anyone diminish us because of our age," Williams wrote in the Instagram caption. 'X-FILES’ STAR DAVID DUCHOVNY SHARES HOW HE CONQUERED HIS ‘NUMBER ONE FEAR’ LATER IN LIFE "I’m 77.

More creative, healthier, busier, more curious — and more alive than I was at 40," he continued, crediting his partner, "good lovin’," kindness, adventure and "a little discipline" for his outlook.

He added that there are "mountains still worth climbing," and lastly gave "the absolute refusal to let anyone else decide my worth" as a reason for why he's thriving.

Williams also encouraged his followers to continue pursuing their goals.

"We didn’t come this far to become invisible," he wrote.

"We came this far to become unstoppable.

We’re not winding down.

We’re still winning — and we haven’t even played our best hand yet." Williams’ message of vitality comes decades after he experienced the overwhelming side of fame while "Happy Days" was at the height of its popularity.

In a previous interview with Fox News Digital, Williams recalled being mobbed by thousands of fans during a concert at the Del Mar Racetrack in California.

LIKE WHAT YOU'RE READING? CLICK HERE FOR MORE ENTERTAINMENT NEWS "I ended up face-down.

On the field.

Literally, I couldn’t breathe," he said.