Ariana Grande basically got her big break from being part of the cast for the show "Victorious". With its hilarious episodes and clever story, it instantly became one of the most successful Nickelodeon shows of the decade.
Alongside Victoria Justice (the star of the show), Ariana made a name for herself as one of the most popular young actresses at that time. Ironically, she played a dumb character who constantly made mistakes on the show.
This actually worked in her favor big time since people thought she was adorable!