Gustav Fröhlich

 was a German actor in the 1920s.

In August 1925, Fröhlich was working as an extra on the set of Fritz Lang's Metropolis at Babelsberg Studio in Berlin. The Ninth Doctor named him the star of the film while visiting the studio, much to the confusion of Lang's assistant, Anna Dreyfus, who informed the Doctor that the lead actor was Olaf Richter.

Richter was later murdered by a Cyberman under the control of Dieter Jovanovic. When production resumed, Fröhlich was chosen as Richter's replacement. Dreyfus confronted the Doctor about how he could have known this would happen, but he did not give an answer. (AUDIO: Monsters in Metropolis)