The Princess Diaries: Third Time Lucky - Meg Cabot

Mia's got everything a girl could possibly want. She's a princess - and she's got a boyfriend! But that's where it all goes wrong. Because Kenny is just NOT the guy she really wants. Michael's the one she's loved forever - but he's going out with someone infinitely cleverer than Mia. Someone who can clone FRUIT FLIES, for heaven's sake! Will the story end happily ever after for the Princess of Genovia?