Max von Essen
Robert Fairchild and Leanne Cope star in the new production.
The new Gershwin musical will play Paris' Théâtre du Châtelet before coming to New York City.
Rachel deBenedet, Drew Gehling, and Autumn Hurlbert were also among the stars participating in the April 5 event.
Max von Essen and Erin Davie are among the Broadway vets who will sing the songs of the acclaimed lyricist.
Tony winner Billy Porter, Patricia Morison, and Max von Essen also came out to the event, which benefits Broadway Cares/Equity Fights AIDS.
The 1960 musical completes the company's Musicals in Mufti Series celebrating the work of lyricist Sheldon Harnick.
Guests will also include Jenny Powers, Donna Bullock, and Rachel de Benedet.