The two-time Tony winner explores arts education at four Los Angeles organizations in the new special.
Composer Ingrid Michaelson also chats with host Clarkson about the new Broadway musical.
The song will be heard in Peacock's upcoming event series The Tattooist of Auschwitz.
Created, written, and narrated by Tony winner Buckley, The Mayfly is a love letter to music and New York City.
Da'Vine Joy Randolph and Halle Bailey are also in the cast, with Pharrell Williams producing.
Lissette Feliciano is set to write and direct.
The mononymic star is currently promoting her newest film Challengers, where she stars opposite Tony nominee Mike Faist.
Other Broadway names appearing in the festival's works include Trey Parker and Matt Stone, Rosie O'Donnell, Jesse Tyler Ferguson, and more.
Tony nominee O'Hara is set to direct the feature film adaptation of his comedy, which played The Public Theatre in 2015.
The play is also eyeing a Broadway transfer next season.
Emmy winner Paul Walter Hauser will play the late Saturday Night Live actor.
The Tony nominee will play a mother in search of her missing daughter on the long-running crime drama.
The Emmy-winning actor will play Dr. Dillamond in Jon M. Chu's screen adaptation of the Broadway hit.
The film will be helmed by Todd Phillips, who produced A Star Is Born.