WASHINGTON - "Saturday Night Live" comics on Tuesday were celebrating the work of Tina Fey -- best known for her Emmy Award-winning impression of Sarah Palin -- as the comedienne and writer receives the nation's top humour prize at the Kennedy Center.

At 40, Fey is the youngest to be honoured with the Mark Twain Prize for American Humor that was created in 1998. She's the third woman to receive it after Lily Tomlin and Whoopi Goldberg.

SNL's Seth Meyers worked with Fey on her Palin sketch and always enjoys it when she comes back to work on the long-running show.

"You can't learn talent," he said. "But you can learn work ethic. She's the hardest worker. She's an assassin."

Fey said before the show that the award was humbling.

"All of the other people who received this prize are heroes of mine," she said. The honour is special because it's not just from the entertainment world but the Kennedy Center and the larger performing arts world, she said.

Earlier, when the prize was announced, Fey hinted she didn't feel worthy, joking that she assumed Betty White was disqualified "for steroid use."

Not to be outdone, on the red carpet, the 88-year-old White praised Fey's "intelligence and her sense of comedy."

However, she deadpanned, "Too bad she's not good looking."

White also will take the stage to honour Fey. They performed together on "SNL" in May for which White won rave reviews as host.

The humour prize honours those who define contemporary comedy. Last year, it went to Bill Cosby. Organizers said Fey made her mark as the first female head writer on "SNL" as well as her Palin impression.

Steve Martin, Jennifer Hudson, Steve Carell and Jon Hamm also will honour the comic.

Martin, who also has taken home the award, said Fey's win means he's been demoted. He said he loves Fey's parody of Palin, but even more, he said he loves to read her writing.

Fey got her start with Chicago's The Second City improv group. She worked on "SNL" for nine seasons and went on to create the NBC comedy series "30 Rock," in which she stars with Alec Baldwin. On the big screen, Fey recently starred with Carell in "Date Night" and is a featured voice in "Megamind," which debuted at No. 1 at the box office last weekend.

Amy Poehler, one of Fey's best buds from SNL, said she's not surprised at all that Fey is winning the top comedy prize.

"Tina's work has been so incredible for so long, it certainly deserves many prizes," she said.

SNL's Fred Armisen said one of his favourite things about Fey is her take on the world.

"She makes fun of people really well -- under her breath. It's so funny, so sharp."

Steve Carell, who overlapped her time at Second City in Chicago, said Fey is "a pretty cool cucumber. She is a very funny person, but she is surprisingly down to earth as well," he said.

Fey is working on her first book, a memoir due out next year. She lives in New York with her husband, Jeff Richmond, and their daughter.

The show will be broadcast nationally Sunday on PBS.