People.com said the buzz was sparked by Simmons' Monday night appearance on "Dancing with the Stars" during which the bubbly celebrity looked unusually thin.
His representative Tom Estey told the celebrity news Web site Tuesday, "He's the healthiest he's ever been.
"He's actually at the weight he was when we launched the original 'Sweatin' to the Oldies' [workout videos in the 1980s,]" Estey said. "He is completely healthy, happy and fit as a fiddle. He's happy. Everything with him could not be better."