Matt Damon and George Clooney stunned gym-goers in Cambridge when they turned up at council-run Kelsey Kerridge Sports Centre for a workout session.The Hollywood A-listers are shooting their new movie 'The Monuments Men' at the Imperial War Museum in nearby Duxford, Cambridgeshire and they stunned regulars at the council run Kelsey Kerridge Sports Centre this past weekend when they casually took advantage of the facilities - which were free for the weekend as part of a promotional offer.'Bourne Identity' star Matt first used the fitness centre on Saturday (01.06.13) for an hour-long weight training session and returned the next day with his Oscar-winning co-star.Centre manager Liane Shadrack told BBC News: "We got a call on Saturday night to say Matt Damon wanted to come along in about five minutes' time to work out in gym. So we just let him in, and he got on with it."The 42-year-old actor appeared to enjoy his time at the gym so much he booked a second session for Sunday (02.06.13), this time with George, 52, for a friendly game of basketball.Liane added: "They shot a few hoops but I did feel a bit bad throwing them out after their hour was up."The gracious Hollywood pals spent time signing autographs and posing for pictures with fellow gym fanatics after their sweat session, and were said to be "lovely".The gym manager added: "They were very nice, such lovely people, and they posed for some pictures and chatted with people, but they didn't say anything about the film they were making."