King, who watched the show from the audience, took the stage following the evening performance, surprising much of the cast. She also performed her hit "You've Got a Friend" along with the company in front of a delighted audience, a representative for the production confirmed to Playbill.com.
King had previously stated she would not attend the musical, which chronicles her rise to stardom and the recording of her album "Tapestry," due to the personal and sometimes painful nature of the show. The musical opened to strong reviews, with praise for leading lady Jessie Mueller, who portrays King. Read the reviews here.
Family and colleagues previously spoke about King's reservations about watching her life play out on stage.
"I support Carole's feelings," added Cynthia Weil, King's longtime friend and half of the equally successful tune-making team of Cynthia Weil and Barry Mann. "This show is very revealing and painful. There are moments she doesn't want to live again."
Based on King's life and music, Beautiful began previews Nov. 21, 2013, prior to an official opening Jan. 12 at the Stephen Sondheim Theatre.
Paul Blake and Sony/ATV Music Publishing produce the musical that features a book by Academy Award nominee Douglas McGrath, who collaborated with Woody Allen on the screenplay for "Bullets Over Broadway." He also penned "Infamous" and "Emma."
Watch King's appearance below: