Brothers Emil and Dariel have been learning how to play the cello ever since they were four years old. And they’ve had a very special teacher, their Russian grandfather who immigrated to America with nothing but the clothes on his back and his cello.

Now, the two wanted to pay grandpa back for all the years of music lessons by making him proud and performing on America’s Got Talent. The two brothers performed an unexpected rockin’ cover of the Jimi Hendrix classic Purple Haze. They blew away the judges and the audience, and now their performance has gone viral online!