The "Poker Face" singer — who has been photographed getting around in a wheelchair since canceling her world tour in February to undergo hip surgery — worked out April 11 at Reform Chicago in the River North neighborhood, owner Corinne Clifton said.

"(Her people) emailed us and asked if they could rent out the studio," Clifton said "I told them we don't rent out the studio, and they came back and said 'Can you do it for a VIP?' I thought about it and was like 'OK, it depends on who it is.'"

Clifton eventually learned it was for Gaga and scheduled her for private lessons at the non-traditional pilates studio April 9 and 11. Gaga didn't show April 9, but her security guards did to check out the studio. They returned with Gaga two days later.

"It was myself and another trainer in the studio with (Gaga) and her personal assistant," Clifton said. "She seems to be in good health. She was walking around totally fine. But her range is limited on her right side. She didn't seem to be in pain, but we were also going really slow. I felt like she could have done more, maybe, but we also didn't want to push her the first time."
Those hoping Gaga's workout attire that day was as outrageous as many of the other unique outfits she's been seen in will be sorely disappointed.

"She was in black stretch pants and a black T-shirt," Clifton said of Gaga, who visits Chicago often because her boyfriend Taylor Kinney is shooting NBC's "Chicago Fire" here. "Not a lot of makeup. She's very pretty and in great shape."