World's first film with a single actor

Malayalam film 'The Gaurd' released in 2001 is the first film with a single actor. Actor Kalabhavan Mani is the lone actor in the film who plays the role of a forest guard. 

Hakim Rawther had written and directed the movie. Jointly produced by Sabitha Jayaraj and Kerela State Film Development Corporation. 

The film had 7 songs sung by the actor himself. Despite that it failed to get the entry at the Guinness World Records. 


Source: Wikipedia