The celebration of Leonard Bernstein will feature performances by Judy Kaye, Lauren Worsham, and more.
The gathering took place at 54 Below on March 22.
Signature's 2014-15 season will feature three world premiere musicals.
Celebratory events will include panel discussions, performances, and a sing-along.
The first evening also starred Audra McDonald, Philip Quast, and Christian Borle.
The upcoming staged production of the Stephen Sondheim-Hugh Wheeler musical will star Bryn Terfel, Emma Thompson, Jay Armstrong Johnson, and more.