SONDHEIM: The Birthday Concert, a gala celebration held in honor of Stephen Sondheim's upcoming 80th birthday was held at Avery Fisher Hall at Lincoln Center for the Performing Arts on Monday, March 15, with an encore performance scheduled for Tuesday, March 16. Tony Award winner David Hyde Pierce hosted the event, which is being recorded by PBS for future broadcast.

Sunday in the Park With George co-stars Mandy Patinkin and Bernadette Peters reunited at SONDHEIM: The Birthday Concert, a gala celebration held in honor of Stephen Sondheim's upcoming 80th birthday at Avery Fisher Hall at Lincoln Center for the Performing Arts on Monday, March 15, with an encore performance scheduled for Tuesday, March 16. The pair brilliantly sang their duet from that show, "Move On," while Patinkin also sang "Finishing the Hat" and Peters movingly performed "Not a Day Goes By" from Merrily We Roll Along.

Real-life couple Will Swenson and Audra McDonald both took part in SONDHEIM: The Birthday Concert, a gala celebration held in honor of Stephen Sondheim's upcoming 80th birthday at Avery Fisher Hall at Lincoln Center for the Performing Arts on Monday, March 15, with an encore performance scheduled for Tuesday, March 16. McDonald duetted with Nathan Gunn on a gorgeous version of "Too Many Mornings" from Follies and wowed the crowd with "The Glamorous Life," written for the film version of A Little Night Music. Swenson participated in the show's stirring finale, as hundreds of performers converged to sing "Sunday."

Opera superstar Nathan Gunn took part in SONDHEIM: The Birthday Concert, a gala celebration held in honor of Stephen Sondheim's upcoming 80th birthday at Avery Fisher Hall at Lincoln Center for the Performing Arts on Monday, March 15, with an encore performance scheduled for Tuesday, March 16. In addition to singing "Too Many Mornings" with Audra McDonald, Gunn gave a glorious rendition of "Johanna" from Sweeney Todd.

Patti LuPone thrilled the audience with a spectacular take on "The Ladies Who Lunch" from Company at SONDHEIM: The Birthday Concert, a gala celebration held in honor of Stephen Sondheim's upcoming 80th birthday at Avery Fisher Hall at Lincoln Center for the Performing Arts on Monday, March 15, with an encore performance scheduled for Tuesday, March 16.

Elaine Stritch earned a well-deserved standing ovation for her peerless rendition of "I'm Still Here" from Follies at SONDHEIM: The Birthday Concert, a gala celebration held in honor of Stephen Sondheim's upcoming 80th birthday at Avery Fisher Hall at Lincoln Center for the Performing Arts on Monday, March 15, with an encore performance scheduled for Tuesday, March 16.

Tony Award winner Karen Olivo (left) and her castmates from the Broadway revival of West Side Story performed "America" at SONDHEIM: The Birthday Concert, a gala celebration held in honor of Stephen Sondheim's upcoming 80th birthday at Avery Fisher Hall at Lincoln Center for the Performing Arts on Monday, March 15, with an encore performance scheduled for Tuesday, March 16

Husband and wife Jason Danieley and Marin Mazzie had great fun with "We're Gonna Be All Right" from Do I Hear a Waltz? at SONDHEIM: The Birthday Concert, a gala celebration held in honor of Stephen Sondheim's upcoming 80th birthday at Avery Fisher Hall at Lincoln Center for the Performing Arts on Monday, March 15, with an encore performance scheduled for Tuesday, March 16.

John McMartin sang "The Road You Didn't Take," which he introduced in the original Broadway production of Follies, at SONDHEIM: The Birthday Concert, a gala celebration held in honor of Stephen Sondheim's upcoming 80th birthday at Avery Fisher Hall at Lincoln Center for the Performing Arts on Monday, March 15, with an encore performance scheduled for Tuesday, March 16.

Matt Cavenaugh and Jenn Colella performed "You're Gonna Love Tomorrow" from Follies at SONDHEIM: The Birthday Concert, a gala celebration held in honor of Stephen Sondheim's upcoming 80th birthday at Avery Fisher Hall at Lincoln Center for the Performing Arts on Monday, March 15, with an encore performance scheduled for Tuesday, March 16.

Bobby Steggert and Laura Osnes performed "Love Will See Us Through" from Follies at SONDHEIM: The Birthday Concert, a gala celebration held in honor of Stephen Sondheim's upcoming 80th birthday at Avery Fisher Hall at Lincoln Center for the Performing Arts on Monday, March 15, with an encore performance scheduled for Tuesday, March 16.

Michael Cerveris and George Hearn performed Sweeney Todd's "Pretty Women" -- and also joined Patti LuPone for a sparkling take on that show's "A Little Priest" -- at SONDHEIM: The Birthday Concert, a gala celebration held in honor of Stephen Sondheim's upcoming 80th birthday at Avery Fisher Hall at Lincoln Center for the Performing Arts on Monday, March 15, with an encore performance scheduled for Tuesday, March 16.

Laura Benanti sang "So Many People" from Stephen Sondheim's first show, Saturday Night, at SONDHEIM: The Birthday Concert, a gala celebration held in honor of Stephen Sondheim's upcoming 80th birthday at Avery Fisher Hall at Lincoln Center for the Performing Arts on Monday, March 15, with an encore performance scheduled for Tuesday, March 16.

Joanna Gleason and Chip Zien sang "It Takes Two" from Into the Woods at SONDHEIM: The Birthday Concert, a gala celebration held in honor of Stephen Sondheim's upcoming 80th birthday at Avery Fisher Hall at Lincoln Center for the Performing Arts on Monday, March 15, with an encore performance scheduled for Tuesday, March 16.

Stephen Sondheim joined the cast to take a well-deserved bow and say a few words at the end of SONDHEIM: The Birthday Concert, a gala celebration held in honor of Stephen Sondheim's upcoming 80th birthday at Avery Fisher Hall at Lincoln Center for the Performing Arts on Monday, March 15, with an encore performance scheduled for Tuesday, March 16.