I ordered this book as soon as it came out because I was obsessed with this series for many years and it still holds up.
This book is told in the same diary format as all the previous books and it is still just as hilarious. Although it was really fun to able to read another book about Mia I totally understand why she stopped writing them when she did and surprisingly I think I liked this book less that most of the early ones. I also thought that considering the title of the book is Royal Wedding that she would get engaged pretty early on, rather than like 150 pages in, which frustrated me a bit when she was complaining about why Michael was acting weird when everyone clearly already knew why. My favourite character in this book was Mia, I hadn't read anything new from her in six years and it was so wonderful to have her hypochondriac, sarcastic self back in my life. I would recommend this book to anyone who liked any of the other princess diaries books.
Mia is now working in a centre that she opened in Mr Giannini's (who is now dead) name that helps teenagers with their academic studies. Michael takes her on a romantic getaway for her birthday where he proposes and she says yes. She returns home and finds that her Grandmere has discovered she has a half sister that is 12 and her dad has known about her for her entire life and has been letting her live in New Jersey with her aunt and uncle after her mother died. Mia ends up going to see Olivia, her sister, and taking her to meet her dad who she apparently had been writing letters to for her entire life. Her dad doesn't want to let Olivia go now he has her so he applies for custody and manages to get her aunt and uncle to give her up by threatening them with looking into what all his money he had been sending them was going towards. Mia then finds out that she is pregnant, with twins, her parents get back together and she and Michael get married.