Title of George Lucas's professional film directorial debut. It was adopted from his 1967 student film THX 1138:4EB The Electronic Labyrinth. Debuting in 1970 it starred Robert Duvall in the title role. THX 1138 has managed to show up in almost all of Lucas's films, in American Graffiti it was on the license plate of one of the cars, in Starwars it was the call sign of one of the Stormtroopers on the Death Star, it even made an appearence in the new Starwars movie The Phantom Menace as a marking on the back of a battle droid.