The Tony-nominated actor passed following a 3-year battle with pancreatic cancer, according to his rep.

The MCC Theater, an off-broadway space Bob founded, released a statement, saying he "lived fearlessly and with great curiosity, good humor, a boundless passion for connection, and a whole lot of heart. We will miss him deeply and always."

Fans of "The Sopranos" will remember his work as Dr. Bruce Cusamano -- the family physician and next-door neighbor to Tony. He also starred in "Sex and the City," "Guiding Light," and "All My Children," for which he got a Daytime Emmy nom.

Bob, the brother of Patti LuPone, was born in 1946 in Brooklyn -- he graduated from Juilliard School in '68 with a degree in dance. His Broadway debut was the same year, in a production of Noel Coward’s "Sweet Potato."

He later was nominated for a Tony award for his work in the original run of "A Chorus Line" ... even convincing the director to play the role of Zach after the original cast member left the show. He received a best-featured actor Tony nomination for the role.

Bob is survived by his wife Virginia, his son Orlando, his sister Patti, and his brother, William.

He was 76.