Who's that Girl? is an engaging young adult novel written by Alexandra Potter. The story centers around Lily, a teenager who moves to a new town and struggles to fit in. When she discovers a hidden talent for music, Lily's life takes an exciting turn as she joins a band and finds her place among new friends. Who's that Girl? explores themes of self-discovery, friendship, and the power of pursuing one's passions. This book is a delightful read for young adults who enjoy coming-of-age stories and relatable characters.