Carole King on Broadway. In person. At the show about her own life. It was Beatiful.

Music legend Carole King, who penned some of the biggest classic hits of early rock and roll, shocked the audience and the cast of the Broadway musical about her life, "Beautiful: The Carole King Musical." During the curtain call, Carole King walked out on the Broadway stage.

After months of guessing if Carole King would ever come to see the Broadway musical that features dozens of her songs, the pop and rock icon showed up for at Thursday evening's performance of "Beautiful: The Carole King Musical." Carole King finally gave her blessing to the show after skipping it since it  previewed last November and opened on Jan. 12.

Even without Carole King's public endorsement, "Beautiful" broke the house record at the Stephen Sondheim Theater twice. The cast recording of "Beautiful: The Carole King Musical," which came out on Tuesday, debuted as the No. 1 cast recording on iTunes and the No. 41 album over all on iTunes.

The audience for last night's performance got the surprise of a lifetime. King came out as the cast was doing the annual appeal for Broadway Cares/Equity Fights AIDS.

She told the audience "They had no idea."

Carole King then hit the mic for her song "You've Got A Friend" backed by the entire cast.

In a statement after the show, King said "It was an honor to see Beautiful for the first time last night. Jessie Mueller and company are fantastic, and it was so joyous to be there. I couldn't be more proud."

"Beautiful: The Carole King Musical" tells the story of a young New York City musician who gets a collaborator, at the piano and at home, Carole King's ex-husband Gerry Goffin.

When the show opened, King told Playbill.com "I already went through this. It's very painful to live through it again."

King's daughter and manager, Sherry Kondor, said Carole King walked out of the reading. Kondor daid "She said, 'I have to go. I can tell it's great, but I can't watch my life played out before me.' "