Hayley Kiyoko Alcroft, known professionally as Hayley Kiyoko, is an American actress, singer-songwriter, musician, 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 in the Disney Channel film Lemonade Mouth. She recently released her debut solo EP and currently guest stars in the ABC Family's series, The Fosters.