Melissa Benoist has portrayed Supergirl on the small screen for three seasons now with a fourth debuting this fall. In a move which sure isn't going to cause brand confusion, DC Entertainment has revealed that a Supergirl movie is in the works. Oren Uziel, the writer behind 22 Jump Street, The Cloverfield Paradox, and Sonic The Hedgehog, is working on the script.
With DC keeping a clear division between its film and TV properties, Tyler Hoechlin portrayed Superman in the TV show while Henry Cavill is on the big screen, it's unlikely that Benoist will reprise her role for the the film.
According to the TV show, Kara Zor-El (Supergirl) is the biological cousin of Kal-El (Superman). She was sent to Earth from Krypton just before the planet's destruction. Her spacecraft was knocked off course and forced into the Phantom Zone, where it stayed for 24 years. By the time the spacecraft crash landed on Earth, Kal-El had grown up and become Superman.