Let's Party (Two Of A Kind, Book 8) by Mary-Kate Olsen
Meet Mary-Kate and Ashley, the Tween Queen Twins! Your new best friends have just arrived...
Ashley has a great idea! She's going to give a party for her best friend, Jennifer. But Ashley gets a surprise too - when she finds out that Mary-Kate is giving another party for HER best friend Amanda on the same night!
But the biggest shocker of all is the one Dad has for both of the girls - one that's going to change their lives BIG-time...
By Megan Stine.
From the series created by Robert Griffard and Howard Adler.