This will be Gomez’s first appearance on the Oscars stage.
Poehler and Yang both rose to fame on Saturday Night Live, which is enjoying an especially high profile as it celebrates its 50th season.
Diane Warren and Brandi Carlile are among the nominees participating; Nile Rodgers and Paul Williams will moderate.
The Academy intends to focus on the songwriters this year rather than have performances of their nominated songs.
March 2 show will also bring back the "Fab Five" presenter concept, and salute fire-scarred LA.
Oscar nominations-round voting opened this morning. Many L.A.-based voting members had more pressing concerns.
Members of the music branch will choose the five nominees for best original song from a shortlist of 14 songs, rather than the customary 15.
Among the music-focused films that are M.I.A.: Elton John: Never Too Late, The Greatest Night in Pop and I Am: Celine Dion.
The times, they are a-streamin'.
The projects are vying for nominations in the documentary feature film category.
