John Goodman is looking good, and he knows it.

When the 57-year-old actor stopped by the “The Late Show with David Letterman” last night, he acknowledged what many in the industry have already noticed: Goodman has dropped some obvious weight.

The weight loss, he joked, is “kind of like letting the gas out of the balloons up on 77th street every Thanksgiving.” Goodman mused his all-time high was somewhere around 400 pounds.

The weight gain sounded like it was a gradual process. “I’d get off 'Roseanne,' ” he started to explain before pausing, thinking about what he just said, and started again with “Every spring, I’d lose 60 pounds…and then I’d gain it all back and [then] some every year.”

Goodman was a bit evasive on the reason – it sounded like knee replacement was at the root of it – but whatever lead to his decision to drop the pounds, he said he is feeling better as a result.

“It’s like night and day,” he said of his new size, adding that he hasn’t reached his goal weight just yet. "I'm going to base it on the fat content of my body – whatever is healthy and right," he said. "It’s going to be an ongoing process for the rest of my life.”