Mia Thermopolis (Anne Hathaway) is the average teenager - sweet, a little geeky, and pretty much invisible to everyone with the exception of her mother, best friend Lilly (Heather Matarazzo) and Lilly's older brother Michael (Robert Schwartzman). Making it through high school without throwing up is a challenge in itself for Mia, so it doesn't come as welcome news when her estranged grandmother, Queen Clarisse Renaldi (Dame Julie Andrews), shows up out of the blue and calmly informs her that she is in fact the heir to the throne of a European country called Genovia. Suddenly Mia's life is thrown into complete overload. She's being taught about scarves, waves, and pears in order to become a perfect Princess, she gets a makeover and a tough looking, yet sweet bodyguard and limo driver called Joe (Hector Elizondo). Things get out of hand when the media gets a hold of the story and suddenly Mia is thrust into the spotlight in the newspapers and in school. On top of all of that, Mia has a choice to make. She must decide by Genovia's Independence Day Ball whether she will relinquish her claim to the throne or to become the Princess and heir to the throne her father, Philippe Renaldi (Rene Auberjonois), and grandmother want her to be.