In the photos, Schwarzenegger poses in a simple black outfit — a t-shirt and shorts paired with a gold watch and sunglasses.

In his caption, the Predator star skipped traditional birthday wishes, choosing instead to direct his fans' attention to his fitness project, the Pump Club.

"Today I turn 79. I don’t want any gifts," Arnie wrote. "Instead, my team and I are turning the fitness industry upside down."

Fans didn't hesitate to shower the legend with praise:

• “Happy birthday! 50 years ago, you had the best physique in the world, and half a century later, you’re still training with the best body for your age!”

• “You inspired an entire generation and continue to do so to this day.”

Behind the longtime fitness icon are seven Mr. Olympia titles and the status of an ultimate idol to millions. However, the actor himself has previously admitted that aging hasn't been easy for him. In a 2023 interview with Howard Stern, Schwarzenegger spoke candidly about his struggles with accepting his age:

“Every day, when I look in the mirror, I smile and think: 'Yeah, it sucks.' When for years you’ve been praised as having the perfect body, where you could see every vein on your abs and chest, and then you fast forward 50 years and you don’t see that anymore... It just sucks. In my 30s or 40s, I never even thought this would happen.”