Peta Sergeant is an Australian-Malaysian actress. Born in 1981 in Malaysia, she grew up in Brisbane, Australia. In high school she dreamed of becoming a marine biologist, but her passion for dramatic acting prompted her to audition and enroll at the National Institute of Dramatic Art. She graduated in 2000 at the age of twenty. Despite landing television roles immediately after drama school and even producing a play, Peta decided to leave the industry and traveled abroad for eighteen months, which helped her establish herself in the acting profession. Among her notable television work are the British science fiction and drama series Jeopardy and Headland, as well as numerous Australian drama series such as Last Man Standing, All Saints, Canal Road, and Satisfaction.

She appeared in the films Iron Sky and Underground. In 2020, Sergeant played Terisa Kerrill in the video game Star Wars: Squadrons. In 2021, she joined the cast of the series Supergirl as the magical imp Nxyly/Nyxy, a fifth-dimensional imp similar to Mr. Mxyzptlk (who was played by her Once Upon a Time co-star Peter Gadiot before being replaced by The Odd Couple actor Thomas Lennon).