Shirtless Christopher Schwarzenegger shows off new slim physique on boat

Christopher Schwarzenegger ditched his shirt to show off his dramatic new fitness transformation while on vacation.

In a snapshot shared by sister Katherine Schwarzenegger on Sunday, the 27-year-old stood on a boat smiling while displaying his sculpted muscles.

He wore a pair of blue striped swim trucks and sported a subtle goatee while mischievously pointing at the water.

Another pic showed the son of journalist Maria Shriver and former California governor Arnold Schwarzenegger with a friend in a bikini top and skirt as they enjoyed the sunny boat ride.

Katherine, 35, also shared a sweet PDA pic with husband Chris Pratt, 46 — the pair sat side by side on the boat, with the “Guardians of The Galaxy” actor closing his eyes in bliss. Two additional snapshots showed Shriver, 69, submerged in the water.

“Lake Days,” Katherine captioned the family-themed post, alongside a blue heart emoji.

A nearly unrecognizable Christopher previously showcased his weight transformation in another photo carousel shared by Katherine in August.

A snapshot showed Christopher leaning against a boat’s edge while checking out his phone in a fitted button down shirt and shorts.

In August comments, fitness icon Arnold addressed how he and other family members — including ex-wife Shriver — supported Christopher’s weight loss journey during his youth.

“I could never go and say to him, ‘You’re overweight,’” the “Terminator” star, 78, told the Times in June.

“We just kept introducing healthy foods,” he added. “We introduced him always to the gym and all of that kind of stuff.”

But, according to the “Expendables” actor, it came down to personal initiative for his son.

“And then, out of nowhere, he decided that he wanted to be lean,” Arnold said at the time. “And now he is. So that is, of course, fantastic, the self-discipline and the self-motivation. I always felt one day it will have to come from him — and it did.”

In May, Christopher confessed he didn’t yet feel he’d completed his health journey. “When you’re saying, ‘oh, before and after photos’ … I don’t feel like I’m an ‘after’ yet. I don’t feel like I’m at that point,” he shared at the Inaugural Beacher Vitality Happy & Healthy Summit in May.