Marnie McPhail Diamond is a well-known American-born Canadian actress and musician. She is famous for her roles as Maria Wong in Braceface, Annie Edison in The Edison Twins, and Peaches in JoJo's Circus.

McPhail was born and raised in Columbus, Ohio, U.S. She later moved to Toronto, Ontario, where she attended the Etobicoke School of the Arts. When she was 14 years old, she got her first major role as Annie Edison in the children's television series The Edison Twins (1982).