Arnold Schwarzenegger’s youngest son Christopher turned heads with his impressive transformation in a new family pH๏τo — and he didn’t need to flex to make a statement.

While big brother Patrick, 31, has been flaunting his physique on The White Lotus, Christopher, 27, let his progress do the talking in a snap shared by sister Katherine Schwarzenegger, 35, on Instagram Thursday in honor of National Sibling Day. 

Also pictured was sister Christina, 33.

Dressed casually in a fitted navy tee and gray shorts, the once reclusive Schwarzenegger sibling looked fit, confident, and nearly unrecognizable from his former heavier-set appearance. 

His latest look is the result of a quiet fitness journey he began back in 2020.

And it seems he may be taking notes from his gym-obsessed half-brother Joseph Baena, 25, Arnold’s son with the family’s former housekeeper Mildred Baena.

Arnold Schwarzenegger ’s youngest son Christopher turned heads with his impressive transformation in a new family pH๏τo — and he didn’t need to flex to make a statement; (Christopher, Katherine, Christina, Patrick)

While big brother Patrick, 31, has been flaunting his physique on The White Lotus , Christopher, 27, let his progress do the talking in a snap; (seen in 2018)

Dressed casually in a fitted navy tee and gray shorts, the once reclusive Schwarzenegger sibling looked fit, confident, and nearly unrecognizable from his former heavier-set appearance; (seen on left in 2018)

The action icon’s affair with Mildred remained under wraps for years. 

In 2010, the revelation that he had fathered her son Joseph ultimately brought his marriage to Maria crashing down. 

While Joseph has long followed in Arnold’s fitness footsteps — frequently showing off his bodybuilder physique — Christopher has recently carved out his own wellness path, emerging with a striking transformation of his own. 

Read More Patrick Schwarzenegger shares surprising reaction from fiancee about incest scene in The White Lotus

Back in 2020, a source told HollywoodLife that Christopher had made it a personal mission to ‘get healthy for graduation’ from the University of Michigan, a goal he ‘stuck to.’

‘He started working out and making better food choices. He was away at school living like a typical college kid for a few years, but he’s growing up now and ready to take better care of himself,’ the insider shared.

Instead of chasing quick fixes or trendy crash diets, Christopher reportedly cut back on junk food and committed to a consistent workout routine.

It was all reportedly part of an effort to mirror his father’s famously disciplined approach to fitness. 

While his visible results have sparked speculation, it’s unclear whether weight-loss aids like Ozempic may have played any role. 

While his visible results have sparked speculation, it’s unclear whether weight-loss aids like Ozempic may have played any role; (seen in 2022)

Christopher’s mother Maria Shriver (top center) split from his father after his affair with their housekeeper Mildred Baena and their son Joseph Baena came to light in 2010, but they still maintain friendly relations when around the kids

And it seems he may be taking notes from his gym-obsessed half-brother Joseph Baena , 25, Arnold’s son with the family’s former housekeeper Mildred Baena 

His efforts to live a healthier lifestyle have even impressed his family.

When Christopher celebrated his 24th birthday, both his father Arnold and brother Patrick commended him on his exercise regimen.

‘Between your boxing classes, your weightlifting classes, your stretching classes, your cycling classes, and on and on, I can’t even keep up with you!’ his famous bodybuilder father raved on Instagram.

Patrick wrote, ‘Proud of you. New job. Crushing in the gym. Whole new person. Can’t wait to see what this year brings.’