Millie Bobby Brown Sings Katy Perry's 'Firework' at Argentina Comic Con - Video

Millie Bobby Brown surprised just about everyone this weekend at Argentina Comic Con in Buenos Aires.

After talking about Eleven and the upcoming season of the show, the Stranger Things actress treated her fans to an impromptu performance of both “Ave Maria”, and Katy Perry‘s “Firework”!

Watch the video of Millie‘s performance below!

PHOTOS: Check out the latest pics of Millie Bobby Brown

Millie told the crowd about her attraction to Eleven: “She is powerful, iconic, a woman and a hero.”

“I loved it (the look of Eleven) and knew right away that I would love the complete look to the character.”