Alicia Keys Sings on a Broadway Stage for the First Time at Hell’s Kitchen

She’s conquered the Grammys, topped the global charts and written music that has defined a generation.

But on Friday, Sept. 26, after two decades in the spotlight, Alicia Keys did something she’d never done before: performed live on a Broadway stage.

The singer-songwriter, 44, surprised audiences at the Shubert Theatre in New York City, joining the cast of Hell’s Kitchen — the hit musical inspired by her own life and music — for the show’s final number, “Empire State of Mind.”

PEOPLE was in the audience for the moment. Her appearance brought the sold-out crowd onto their feet, theatergoers cheering along as she sang her Big Apple anthem.

Of course, fans expected to see Keys on Friday night, only not that soon. She was scheduled to launch the first in a two-night event called the Encore Sessions with Alicia Keys, a series of intimate post-show performances alongside members of the show’s cast.

“So excited that you’re here with us tonight for the very first Encore Sessions,” Keys said, as she returned to the stage after the cast curtain call. “Please give it up for the cast and the crew and the musicians. Honestly, that’s the first time that I joined them on stage for that. That felt real good just now. So this was a really beautiful thing.”

“What we wanted to do was bring you through a special experience, something that truly never happens in the Shubert Theater,” she continued. “This would be officially my first time on a Broadway stage, and you’re here with me, so I want to say thank you so much.”

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Keys went on to share the theme of the post-show event, explaining that she would be spotlighting songs that didn’t make it into Hell’s Kitchen during the development process. The musical blends Keys’ most iconic hits — from “Fallin'” to “No One” to “If I Ain’t Got You” to “Girl on Fire” — with new songs written exclusively for the stage to tell a coming-of-age story inspired by Keys’ life.

Building the show alongside director Michael Greif and book writer Kristoffer Diaz came with some moments of conflict, Keys said. “I have to tell you, I gave them some hell about some stuff. And I got to tell you that Michael Grief was always right!” she laughed. “I was like, ‘We are not doing that, I’m telling you, we are not.’ And then he’s like, ‘Just try it?’ and I was like, ‘Ugh!’ And then we’d try it and I’d be like, [disappointedly] ‘You’re right.’ ”

One of those moments Keys fought for was between the mother-daughter duo of Ali and Jersey (currently played by Amanda Reid and Jessica Vosk).

“I envisioned it that Jersey and Ali would have this stand-off with this song, trying to convince each other that they were more of this than the other,” Keys said. “We worked on this for a couple of workshops, and I thought this was working. And then when it wasn’t working, Michael told me I had to write another song. I was pretty bummed out. But it was beautiful because he pushed me to be able to write what I consider my first musical theater song, which was ’17.’ And that’s now what lives in the piece.”

So what was the song that Keys wanted in that spot? Her 2007 hit “Superwoman,” which she performed with Vosk.

Vosk wasn’t the only Hell’s Kitchen cast member who joined Keys on stage. Tony winner Kecia Lewis sang with Keys on 2001’s “A Woman’s Worth,” while Tony nominee Christopher Jackson duetted with Keys on 2012’s “Not Even the King.”

The night’s final number was “Unbreakable,” which was off of Keys’ chart-topping 2005 Unplugged album. The 17-time Grammy winner is honoring the LP’s 20th anniversary with a new vinyl release out Oct. 3.

“The Unplugged album is such a beautiful, monumental moment,” Keys said. “I’m so excited to celebrate this milestone. I can’t believe it, because I swear it was just yesterday. Like, I swear! I was there just yesterday so don’t know what happened!”

After wrapping her concert, Keys thanked the audience, telling them, “I adore you with all my heart.”

Hell’s Kitchen features Angela Birchett, Chad Carstarphen, Reid Clarke, Nico Dejesus, Mykhel Duckett, Adriel Flete, Vanessa Ferguson, Lulu Oro Hamlett, Jakeim Hart, Takia Hopson, Gabriel Hyman, Lindsey Jolyn Jackson, Eliazar Jimenez, Kelsee Kimmel, Jackie Leon, Raechelle Manalo, Miki Michelle, Benjamin H. Moore, Onyxx Noel, Susan Oliveras, Amma Osei, Sarah Parker, Eric Parra, Aaron Nicholas Patterson, William Roberson, Niki Saludez, Mariand Torres, Maggy Van Den Heuvel, Nyseli Vega, Lamont Walker Ii, Keenan D. Washington and Oscar Whitney Jr.

A second performance of Keys’ Encore Sessions is set for Saturday, Sept. 27. VIP packages include premium seats, a merchandise bundle and a meet-and-greet with the superstar.

Tickets for Hell’s Kitchen are on sale now.