What a lovely (and handsome) surprise!
Damon, who is in town to film The Monuments Men alongside his actor pal, booked the basketball court at Kelsey Kerridge for an hour around lunchtime.
According to the BBC, the gym's manager, Liane Shadrack, felt bad about kicking the actors out afterwards.
"They shot a few hoops but I did feel bad throwing them out after their hour was up," she said.
The men clearly didn't have any hard feelings towards her, however, and posed for a photo to mark the special encounter.
"They were very nice, such lovely people…they posed for some pictures and chatted with people, but they didn't say anything about the film they were making," she added.
Now if those two could only waltz into our gym, our workout would surely improve.