The film is set to be released on Friday (June 26) and stars Milly Alcock as the titular character.
It is the second film in the DC Universe and was filmed at the facility on the edge of Watford in 2025.
The Watford Observer previously shared photos of filming that were taken by Twitter/X user UnBoxPHD.
Milly Alcock pictured on the set of the new Supergirl film. (Image: UnBoxPHD)
Alcock is no stranger to Leavesden, with the Australian actress also having had a major role as young Rhaenyra Targaryen in Game of Thrones prequel House of the Dragon, also shot at the facility
Pictures showed the construction of some of the sets fans can expect to see when the film hits cinemas.
Others even gave a sneak peek of Alcock wearing the iconic Supergirl suit.
Most famously, the Leavesden site was the home of every Harry Potter film and will serve as the location for the upcoming television adaptation of the series.
(Image: UnBoxPHD)