AceShowbiz -

Ariana Grande made an unexpected appearance at Jason Robert Brown's recent concert and reminded fans that she was a Broadway star way before she's popular for becoming an actress and pop singer. During Brown's "The Last Five Years, Parade" show, the petite diva joined the composer to sing some tunes from the Broadway musical "13".

As fans know, Grande and Brown's friendship started seven years ago, when she starred as Charlotte in the musical for which he wrote the music and lyrics. Brown talked to the crowd about his first encounter with the 22-year-old before she showed up on the stage in an oversized sweater and large-rimmed glasses.

Rocking her signature ponytail, she flawlessly belted out three songs including "The Lamest Place in the World" and "Brand New You" from "13". She sang the latter tune as a duet with Broadway star Shoshana Bean.

Grande's brother Frankie Grande was among people attending Brown's concert at the Catalina Bar & Grill in Hollywood. He filmed his sister's performance and proudly shared the video on Twitter Tuesday, January 5.

SURPRISE! @arianagrande just performed 3 songs at @MrJasonRBrown concert 2night & SLAYED!�°ï¿½ï¿½ï¿½�°ï¿½ï¿½ï¿½ should I post the rest?�°ï¿½ï¿½ï¿½ pic.twitter.com/8dZ72kU1QD

— Frankie James Grande (@FrankieJGrande) January 5, 2016