O'Brien revealed his participation in "The Simpsons Take the Bowl," a three-night event at the Hollywood Bowl, during an interview with Buzzfeed UK published Monday.
O'Brien was a writer for "The Simpsons" for two seasons from 1991 to 1993 and wrote one of the show's most enduring episodes, "Marge Vs. the Monorail."
The episode, which was a loose parody of "The Music Man," featured Phil Hartman voicing a slick-talking conman who persuades the town of Springfield to invest in a monorail. One of the highlights of the episode was "The Monorail Song," a quick bit of silliness that will be performed live with the Gay Men's Chorus of Los Angeles and O'Brien singing the role of the conman.
Voice actor Hank Azaria will host the "Simpsons" event, which will feature the show's voice cast, including Nancy Cartwright, Yeardley Smith and guest performers Beverly D'Angelo, Jon Lovitz, "Weird Al" Yankovic and "Simpsons" creator Matt Groening.
The Hollywood Bowl event, with a fireworks finale, will take place Sept. 12-14. The 26th season of "The Simpsons" will debut on Fox on Sept. 28.