Katy Perry Sings "Firework" With the PS 22 Choir 2.58K Whitney Jefferson 03/01/11 10:20AM Filed to: Oprah Oprah Katy Perry TV Ps22 Video Even though she was suspiciously absent from the Oscars (Russell Brand brought his Mother as his date) Katy Perry somehow made it back to town to sing her hit song with the PS 22 kids during Oprah's post-Oscar special.