Ava Acres (born May 13, 2005) is an American actress. She played young Regina in Once Upon a Time and also appears in Agents of S.H.I.E.L.D. as Katya Belyakov, the main antagonist of the episode "Melinda". In addition, she has played Madeline in season 5 of the television series American Horror Story, and young Rebecca in the comedy series Crazy Ex-Girlfriend. Acres' older sister, Isabella, is also an actress. (wikipedia)