George Clooney's mysterious Disney movie has been renamed 'Tomorrowland'.

The 51-year-old actor has been confirmed to star in Brad Bird's ''ultra-secret sci-fi project'', which was originally known by the working title '1952', according to Entertainment Weekly.

Jeff Jensen and 'Prometheus' writer Damon Lindelof will produce the project along with Brad, and the pair have also penned the script, originally thought to have similarities to Steven Spielberg's cult 1977 film 'Close Encounters of the Third Kind', which sees a man make contact with aliens on planet earth.

However, Damon posted a picture of a box of Walt Disney's personal archive labelled '1952' on his Twitter account last week, with the caption: ''The Box... opened''.

The box contained old photographs of Walt, Technicolour film, a history of NASA called 'Model Research', an August 1928 edition of Amazing Stories magazine, and a vinyl record.

After stirring up fans' curiosity, Damon quashed previous reports the film would be an alien invasion movie. The news could support theories it will instead be based on the Tomorrowland section of the Magic Kingdom theme park at Walt Disney World Florida - a Jules Verne-inspired vision of a future that never came to fruition.

He teased on Monday (28.01.13): ''We won't tell you what it's about (yet), but we will tell you what it's NOT about. And that would be ALIENS. #Tomorrowland''

'Tomorrowland' will hit cinemas on December 19, 2014.