To mark the special day, Playbill.com collected some of our favorite musical moments from Mazzie's career.
Mazzie sings "Someday My Prince Will Come" on the "Rosie O'Donnell Show."
The Rodgers and Hart classic "Bewitched" as part of "Divas, A Celebration at Carnegie Hall."
"Happiness" with Jere Shea in the opening scene from Stephen Sondheim and James Lapine's Passion.
"I Don't Care Much" from Cabaret.
Belting out "Unexpected Song" as part of an Andrew Lloyd Webber montage with Judy Kuhn and Audra McDonald.
Performing Scott Burkell and Paul Loesel's "A Sorta Love Song" at Birdland.
With Tony winner Brian Stokes Mitchell performing "So In Love" from Kiss, Me Kate on the "Rosie O'Donnell Show."
Mazzie and Chita Rivera perform "Class" from Chicago.
Mazzie with Donna Murphy and Karen Ziemba, honoring Angela Lansbury at the Kennedy Center Honors.
Mazzie in rehearsal for her 54 Below engagement.
Highlights of Mazzie in Carrie.
Mazzie records "I Remember How Those Boys Could Dance" from Carrie.
Mazzie speaks with Playbill.com about originating the role of Clara in Passion in this new feature for the Playbill Vault.
A look at the Off-Broadway production of Carrie including Mazzie's performances of "And Eve Was Weak" and "When There's No One."
Mazzie and company in highlights from Bullets Over Broadway.