Leo Miller was a Terronite actor.
When theatre was banned on their home world of Terron V, Miller and his fellow out-of-work actor Maximilian Love got jobs as guides in a museum. They found a machine there which could transfer hopes and dreams from one person to another. They stole it and took it to 1920s Earth, where they used it to make Love a better actor by stealing the talent from other actors. The Terronites were stopped by the Tenth Doctor and they were arrested by Earth police. (COMIC: Silver Scream)