Arnold Schwarzenegger has gone undercover as a personal trainer in a video to promote childhood fitness.
The former Mr Universe dressed up in a not-so-convincing disguise of a black wig and moustache at Gold's Gym in Venice, California.
He then walked around the gym pretending to be a personal trainer, and surprised people with questions about their workouts.
The reactions of gym-goers were caught on hidden cameras placed inside the gym.
One person working out noted that while Schwarzenegger "looked so familiar", she could not work out why.
The stunt was carried out to support After-School All-Stars, a non-profit group that encourages childhood fitness.
The video has so far attracted more than 3.5 million YouTube hits.
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