Schooling stunned his idol Michael Phelps to win 100m butterfly gold at the Rio Olympics.
Schooling, who stunned his idol Michael Phelps to win 100m butterfly gold in Rio, grappled with the ONE Championship atomweight champion for the cameras at a gym in Singapore.
"That would be sick," said Schooling, who was accompanied by fellow University of Texas swimmer Tripp Cooper, when asked if MMA should be an Olympic sport.
"I love watching MMA, Tripp loves watching MMA too, sometimes we watch fights together. I know also that the guys in the team also love watching MMA.
"So you know we're guys, we're into that stuff, we're all for it."
Lee said pankration, a fighting sport similar to MMA with boxing, wrestling, kicking, holds and chokes, was contested at the ancient Olympics in Greece.
"Definitely I'm all for it... I want it to be put back into the Olympics because pankration is actually one of the truest forms of MMA and that was in the ancient Greek Olympics back in the day," said Lee.
She added: "It's a shame they took it out."