Will Forte Talks Working with Betty White for 'SNL' (VIDEO)

Working with Betty White for last weekend's episode of 'Saturday Night Live' was the "best week" Will Forte has ever had on the show, he told David Letterman on 'Late Show' (weeknights, 11:35PM ET on CBS). And that's saying something: He's been on 'SNL' for eight years.

"She would just get standing ovations wherever she went," said Forte. "She deserved it, she's wonderful. And she has so much stamina. She came in Friday morning at about 8:30 ... and worked until 12:30 at night. I was very concerned -- this is an 88-and-a-half-year-old woman."

Ah, but no need to be worried. She shared with Forte her secret diet for endurance and long life.