Actors' Equity Association celebrated its 100th birthday with a black-tie gala at the Midtown Hilton Hotel on Monday, June 17. Founded May 26, 1913, the union represents nearly 17,000 professional actors and stage managers living and working in New York, as well as 49,000 members nationwide. On hand to toast the momentous milestone were Broadway veterans including Leslie Uggams, Michael Cerveris, Beth Leavel, S. Epatha Merkerson, and more. Check out the stars in the photo gallery below.