Ariana Grande Visits & Juliet, the Broadway Musical That Features 2 of Her Hit Songs (Exclusive Details)

Ariana Grande went back to her roots over the weekend.

Prior to launching her wildly successful music career, the 30-year-old songstress got her start on Broadway as a star of Jason Robert Brown's short-lived 2008 musical, 13.

On Saturday night, Grande returned to the Great White Way, this time sitting in the audience at the Stephen Sondheim Theatre to see the Tony-nominated musical & Juliet.

It's a show that Grande has a connection to. The musical asks the question, "What if Juliet didn't die at the end of William Shakespeare's Romeo & Juliet?" and uses a string of pop songs — including Grande hits "Problem" and "Break Free" — to tell the story of what happened in her life next.

All of the tunes come from the catalogue of five-time Grammy-winning songwriter and producer Max Martin, who was also in the audience Saturday with Grande.

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Saturday marked the first time Grande had seen the show.

After taking in the performance — to much fanfare from her fellow audience members buzzing about her presence among them — the two friends went backstage where Grande met Tony winner Paulo Szot, Tony nominees Lorna Courtney and Betsy Wolfe, and the rest of the cast.

"She was so sweet and gracious and literally brought her Playbill and asked if anyone had a Sharpie because she wanted the entire cast to sign it," an insider on the scene tells PEOPLE, joking, "once a stage door girl, always a stage door girl!"

While backstage, Grande also met the Tony-nominated choreographer Jennifer Weber, who taught the Grammy winner some of the "Problem" choreography from the show. "She was totally game and danced with the cast," the insider says.

Meanwhile, Grande wasn't the only celebrity in the audience of & Juliet on Saturday.

Actress and talk show host Drew Barrymore was also there with her daughters too. "The audience was so starstruck by Ariana," says the source. "Most people didn't even realize that Ariana was sitting with the songwriter behind all the songs in the show!"

Grande's boyfriend Ethan Slater is in rehearsals right now for the revival of Spamalot, the John Du Prez and Eric Idle stage adaptation of the 1975 film Monty Python and the Holy Grail that is returning to Broadway some 14 years after the original show closed in 2009.  

Slater, 31, will play the dual role of The Historian/Prince Herbert, a part originated by two-time Tony winner Christian Borle. Other principal cast members include Christopher Fitzgerald (as Patsy), James Monroe Iglehart (as King Arthur), Leslie Rodriguez Kritzer (as the Lady of the Lake), Jimmy Smagula (as Sir Bedevere), Michael Urie (as Sir Robin) and and Nik Walker (as Sir Galahad).

Performances begin Oct. 31 at the St. James Theatre with an official opening on Nov. 16.

The day before performance begin, another musical with ties to Grande and Slater will hit a special milestone when Wicked celebrates its 20th anniversary. The show, currently the fourth longest-running show in Broadway history, originally opened Oct. 30, 2003.

It tells the story about what happened between Glinda the Good Witch and Elphaba the Wicked Witch of the West before Dorothy dropped in on The Wizard of Oz.

Both Grande and Slater are starring in the musical's upcoming film adaptation, Grande as Glinda and Slater as Boq, the love interest of Elphaba's younger sister, Nessarose (who would later become the Wicked Witch of the East). The two met on set making the movie, the first part of which is set to release in theaters Nov. 27, 2024.

PEOPLE confirmed the pair were dating in July. Grande and Slater have yet to make a red carpet appearance together, with a source telling PEOPLE last month they were "trying to navigate their new relationship in private."