Ariana Grande

Ariana is now one of the biggest pop stars in the world with seven studio albums and two Grammy Awards under her belt.

But Ariana got her start when she was given the part of ditsy Cat Valentine on 'Victorious', which was set at a high school that focused on the arts.

She later said: "My years filming 'Victorious' were some of the happiest of my life and that cast is family to me."