Calvin Klein Collection and the Peggy Siegal Company threw a congratulatory celebration at the Darby on January 9 in honor of Darren Criss' Broadway debut in How to Succeed in Business Without Really Trying, and the Glee heartthrob wasn’t the only celebrity in attendance. Co-hosted by Tony winner Alan Cumming, Parker Posey, Seminar's Lily Rabe, Book of Mormon star Andrew Rannells and Jordon Roth, the starry guest list also included screen legend Susan Sarandon and Broadway favorites Rose Hemingway, Tony winner Nikki M. James, America Olivo and Tony winner John Benjamin Hickey. Criss played songs for the starry group, including his cover of Katy Perry’s “Teenage Dream,” then kicked back with the party guests. Click on for photos of the star-studded affair, then see Criss at the Al Hirschfeld Theatre in How to Succeed before January 22.