The Terminator star couldn't resist diving in front of the Thai visitors as they were posing for a group shot in front of the Eiffel Tower.

On a bike, in dark glasses, shorts and a camouflage jacket, the actor was understandably unrecognisable to them.

He later thanked them on Instagram for "letting me crash your photo!"

One of the Thai group later said on Pantip that he and his companions were about to smile broadly for the snap when someone "rode his bike in front of our shot".

The tourist, posting as Y-G2006, added: "I thought to myself, 'Hey, what a badass!'"

He also said he and his group had no idea at the time who the photobomber was.

It was only down to their guide shouting "Arnold" once Schwarzenegger had ridden off - accompanied by bodyguards on cycles and motorbikes - that they realised who they had been dealing with.

Schwarzenegger's Instagram account showcases a range of snaps taken on his Parisian adventure.

He's seen outside Notre Dame cathedral and the majestic building of Les Invalides.

"Fantastic bike ride through Paris. I cannot say this enough: to truly appreciate a city, get on a bike," Schwarzenegger wrote.

The actor, and former politician, was in the city after being honoured at the weekend at the Elysee Palace by French President Francois Hollande.

Schwarzenegger was awarded with the country's most prestigious medal, that of a Chevalier de la Legion d'Honneur - for his environmental work.

The actor has long been a supporter of green, renewable energy and has worked with the French leader on promoting its use.

Schwarzenegger, the former governor of California, also met the Mayor of Paris Anne Hidalgo.