WASHINGTON — David Letterman was celebrated Sunday night for his record run on late-night TV, innovative comedy routines and for helping the nation start to heal by reassuring that it was OK to laugh again after the terrorist attacks of Sept. 11, 2001.

Fellow entertainers gathered to honor Letterman at the Kennedy Center, where he was receiving the Mark Twain Prize for American Humor.

Among those attending were previous recipient Steve Martin and late-night host Jimmy Kimmel, who recalled a monologue Letterman gave on his show shortly after 9/11.

“You let us know it was OK to move on and OK to laugh again,” Kimmel said. “Dave, you led the way for all of us.”

Kimmel jokingly blamed the election of President Trump on Letterman’s retirement in 2015.

“It’s like you went out for cigarettes one day and left us in the hands of our abusive, orange stepfather,” Kimmel said.

Comedians Martin and Martin Short needled him about his bushy, white beard.

“Dave has always had excellent instincts. What better time than now to choose to look like a Confederate war general,” Martin said.

The 70-year-old Letterman spent 33 years on late-night TV, hosting long-running shows on NBC and then on CBS. His final broadcast on May 20, 2015, was episode No. 6028 that Letterman hosted. It shattered the record of his mentor, Johnny Carson.

– From news service reports