Hours after announcing his split Tuesday, Carrey was back to work in Los Angeles, filming a promo for Idol Gives Back – American Idol's annual star-studded charity special.
"You would never have known that [the breakup] had just happened," says a source. "Jim is a constant professional."
Carrey, 48, who filmed the spots in an adjacent studio to where the live American Idol telecast was taking place, was joined by fellow funnymen Russell Brand and Jonah Hill – and the three were in high spirits.
"Jim was loose and relaxed," the source says. "It was a lot of fun."
Idol Gives Back will air on April 21.