Workout mogul Denise Austin says Richard Simmons is doing just fine in the shadows ... and she's sharing some of their old fitness routines for folks in quarantine.
Denise tells TMZ ... her old buddy Richard is doing just fine these days, even though he's kept himself out of the public eye for 6 years and counting. Denise says she's in constant contact with Richard's managers, and they assure her he's doing well.
Interestingly, though, she -- like most of the world -- has NOT seen him in person.
Richard and Denise go way back .