Anyone can upload an original song or cover to YouTube and hope that people will notice it. For many famous singers, YouTube was the starting point that helped them turn their passion for music into a professional career.

Some of YouTube’s biggest music sensations weren’t even old enough to drive when they were discovered, let alone launch their own new careers into the spotlight. Yet many of them go on to work with veteran managers, producers, and other big-name artists, sign record deals, release debut singles and albums, and become bigger than they ever thought possible.

Below, check out some of the kids, teens, and young adults who are now having thriving music careers thanks to the viral power of YouTube.

Sophia Grace (and her cousin Rosie) rose to fame after a YouTube video of her rapping to Nicki Minaj's Super Bass went viral. The girls quickly became favorites of Ellen DeGeneres, and both have appeared on her talk show multiple times since their first appearance. In January 2015, Sophia Grace released her own new rap single, titled Best Friends.