Long known for his portly build, the former Roseanne star hit the red carpet at Thursday's AFI Tribute to Mike Nichols in L.A., showing off a dramatically slimmer physique.
The actor turns 58 later this month, and stars in HBO's new series Treme.
In a 1992 interview with Entertainment Weekly, he claimed to be indifferent about his weight, which was around 300 pounds at the time. ''I lose it, I gain it back,'' he said. ''No big deal.''