Billie Lou Watt was an American actress renowned for her pioneering work in providing English voices for Japanese anime, particularly during the 1960s through the 1980s. Born on June 20, 1924, in St. Louis, Missouri, she began her career in theater and radio before transitioning to television and voice acting. Her entry into the world of anime came in 1963 when producer Fred Ladd recruited her and her husband, Hal Studer, to work on the English adaptation of the classic series Astro Boy. This collaboration established her as one of the earliest and most significant voice artists to introduce Japanese animation to American audiences.

Throughout her prolific career, Watt voiced a wide array of lead characters in numerous dubbed anime productions. She is perhaps best known for her roles as the title characters in Astro Boy and Kimba the White Lion, as well as Jimmy Sparks in Gigantor. In addition to these iconic series, she took on leading roles in several feature-length anime films. She voiced the title character, Taro, in Taro the Dragon Boy; the protagonist, Jack, in the 1974 film Jack and the Beanstalk; and Jim in Animal Treasure Island. She also provided the voice for the heroic Hols in the 1968 film Horus: Prince of the Sun. Later in her career, she was a central voice actor in the biblical anime series Superbook, where she played the inquisitive Christopher "Chris" Peeper and, in the second season, the robot Gizmo, among many other characters.

Watt's contributions to anime extended beyond voice acting. Alongside her husband, she frequently wrote dialogue and scripts for the English adaptations of the shows in which she performed. This included writing for Superbook and The Flying House, as well as for the Kimba the White Lion series. Her work was part of a close-knit circle of voice actors in New York that regularly collaborated on these projects, including Ray Owens, Sonia Owens, and Gilbert Mack. Her final voice acting role was as Ma Bagge, the mother of Eustace, on the Cartoon Network series Courage the Cowardly Dog, which aired from 1999 until her death. Billie Lou Watt passed away from lung cancer on September 7, 2001, in New York City, leaving behind a legacy as a foundational figure in English-dubbed anime.