Hayley Kiyoko Alcroft (born April 3, 1991), known professionally as Hayley Kiyoko, is an American actress, singer and dancer. She is best known for playing Velma Dinkley in Scooby-Doo! The Mystery Begins and Scooby-Doo! Curse of the Lake Monster as well as Stella Yamada from the Disney Channel film Lemonade Mouth. Description above from the Wikipedia article Hayley Kiyoko, licensed under CC-BY-SA, full list of contributors on Wikipedia.