Currently in the county to film scenes from his upcoming movie Hobbs and Shaw the wrestler turned actor took a break to work out.
He was filming in Eggborough power station in North Yorkshire when he sent a bodyguard to inspect the World Fitness Gym in Doncaster.
After scoping out the facilities at the bodyguard alerted the owner, Craie Carrera, that Johnson would like to visit.
He told Mr Carrera the trip would have to remain a secret to prevent wild crowds from arriving.
"People were just working out and getting on with their own business when he walked in. They were having kittens when they saw him, I don't suppose they were expecting it,” Mr Carrera said. "I helped him with the work out and pushed him pretty hard, his arms were aching by the end. He was a really down to earth guy, really nice and easy to get on with."
Johnson spent time after his workout posing for photos and signing autographs.
Mr Craie’s wife, Alicia, said: “When he turned up, he was great. He was absolutely wonderful. One member got a shirt signed."
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