Ariana Grande's rise to international pop stardom began when she made her Broadway debut in the 2008 musical 13, which featured music and lyrics by composer Jason Robert Brown. The star paid tribute to the show by joining the Tony winner on stage Monday for a surprise performance at his Hollywood concert.
"I happened to bump into an international pop star the other day and I asked her if it would be fun to sing a tune or two and she said, 'Three,'" Brown joked as he introduced Grande. "And I said, 'Three would be fine.'"
The 22-year-old singer was greeted with loud applause by the audience before performing two songs from the musical, "The Lamest Place In the World" and "Brand New You," along with “Getting Out," a song from Brown's album Wearing Someone Else’s Clothes.
Watch the full video above.