This is the moment Terminator star Arnold Schwarzenegger’s son Joseph Baena shows fans just what he is made of as he runs a triathlon in skin-tight Speedos.

Bodybuilder Joseph was clearly struggling to keep his bulges under control as he jogged along a beach to the finish line in bouncy slow motion.

Joseph, who is also an actor like his lookalike dad, had entered the race in Malibu, California, USA, over the weekend and shared them online to mark his 26th birthday.

In the footage, Joseph has apparently just emerged from a dip in the Pacific Ocean wearing just a pair of Speedos and runs towards the finish line.

Unlike other competitors, he has shunned a wetsuit and seems determined to show off all his bulges.

He later shared the images on Instagram on 2nd October, saying: “Twenty Six? More like Twenty SICK!”

He added: “Here’s your POV of me running into my late twenties.”

Arnie fathered Joseph with his former housekeeper Patty Baena, while he was married to Maria Shriver.

Joseph was 13 years old before he even knew that the megastar was his dad.

Social media users wished him a happy birthday, with some saying he looks more and more like his 76-year-old dad.

One named as ‘tonyalonzo88’ said: “Bro starting to look like Arnold in his golden years…”

While ‘ryan.walsingham’ said: “So cool to watch your transformation. You have a similar physique to your Dad.”

And ‘joe-da-chicago’ added: “Looking more and more like Daddy.”

Like his dad, Joseph has pursued a career in bodybuilding, sports modelling and acting,

In 2022, he was a contestant on the 31st season of America’s version of ‘Strictly’, ‘Dancing with the Stars’.