Supergirl is a 1984 superhero film directed by Jeannot Szwarc and written by David Odell. It is based on the DC Comics character of the same name and serves as a spin-off from Alexander and Ilya Salkind's Superman film series. The film stars Helen Slater as Supergirl, along with Faye Dunaway, Mia Farrow, and Peter O'Toole, with Marc McClure reprising his role as Jimmy Olsen from the Superman films. He was the only actor to do so. Supergirl was the first English language superhero film to feature a woman in the lead role.

References:
https://en.wikipedia.org/wiki/Supergirl_(1984_film)