Moments of absurdity are to be expected at the biennial Night of Too Many Stars benefit on Comedy Central. Things like Seth Rogen auctioning off a trip to the urinal with him; a knock-down, drag-out fight between Kevin Bacon in a butter costume and Liev Schreiber dressed as broccoli; a performance of Call Me Maybe by Carly Rae Jepsen and Harvey Keitel.

All are memorable highlights of the fourth Night of Too Many Stars, which uses comedy to raise money for autism education programs. But at the event, which was taped last weekend at the Beacon Theatre in New York and airs at 8 p.m. Sunday on Comedy Central, something remarkable and unusually tender happened along with Stephen Colbert being mauled by a bear.

A young autistic girl sang a duet of Firework with Katy Perry that brought the house down and moved host Jon Stewart (and many others) to tears. As the standing ovation roared, young Jodi DiPiazza stood up from behind the piano and wrapped her arms around Perry.

“It’s the most beautiful thing I’ve ever been associated with,” said the comedian Robert Smigel, who organizes and produces Night of Too Many Stars. “I’ve made a career of all this nonsense – and I’m very proud of it – but it all pales in comparison to what happened Saturday.”

Perhaps more than any other installment, this year’s Night of Too Many Stars strikes a balance between heart-rending emotion and knee-slapping humor.

Smigel is best known as the comic genius behind the Borscht Belt-inspired hand puppet Triumph the Insult Comic Dog. His career has covered Saturday Night Live, where as a writer he made the TV Funhouse cartoons; Late Night With Conan O’Brien, where he was head writer in a room that included Louis C.K.; and numerous projects with Adam Sandler.

Smigel and his wife, Michelle, have a 14-year-old son, Daniel, who’s autistic. It was their trouble getting him into one of the few quality schools for autistic children that led Smigel to begin the Night of Too Many Stars fundraisers, which prior to this year brought in more than $14 million.

“They deserve to be nurtured,” says Smigel of children with autism. “They deserve to be educated. They deserve to be encouraged and not written off and not ostracized.”

Smigel founded the event by calling on his comedian friends to ask the favor of their participation. Stewart, with whom Smigel hadn’t been close, has been a mainstay.

This year’s show also features Tina Fey and Amy Poehler (who auction off the chance to be their best friend for the night), J.B. Smoove (who makes a DVD commentary watching HBO’s Game of Thrones with Tracy Morgan) and Ben Stiller (who, as his fashion model character Derek Zoolander, dresses down Tommy Hilfiger). On Conan, O’Brien is chipping in by trying to raise $100,000 from his viewers. If he succeeds, he has pledged to do an episode in a deep spray tan.

Musicians this year include Sting, Jepsen and Perry. After the show, Perry tweeted that she would never forget the experience, which she called “the most important moment thus far of what I do.”