Star Wars
Darth Vader finds the source of those set leaks. LucasFilm

After a spate of leaks from the production of Star Wars: Episode 7 a poster has been spotted at Pinewood jokingly warning workers and visitors not to let slip any of the film's many sought-after secrets.

The poster was spotted by renowned film producer Frank Marshall, whose wife Kathleen Kennedy happens to be the person who took control of the Star Wars franchise when she became president of LucasFilm following Disney's acquisition of the firm in 2012.

Production on the film has been in full swing for most of the year, and for the most part director JJ Abrams and his team have done well to keep its secrets to themselves, particularly relating to the characters being played by new lead actors John Boyega and Daisy Ridley.

Which is not to say that they've completely shut up shop either. Videos from the set have revealed some of the movie's locations, background characters and returning vehicles, the latest of which confirming the return of Han Solo's Millennium Falcon.

The poster isn't a new creation for the production however, but one created by artist Cliff Chiang for an Imperial Propaganda series of works.

Star Wars: Episode 7 stars returning trio Harrison Ford, Carrie Fisher and Mark Hamill alongside newcomers Boyega and Ridley, as well as Adam Driver, Lupita Nyong'o, Andy Serkis and Max von Sydow, among numerous others.

The film will be released on 18 December 2015.