Classic comedy Monty Python and the Holy Grail is getting a special one-night-only re-release in the UK to mark the film’s 40th anniversary. Park Circus and Sony Pictures will release the 1975 gaffer in over 500 UK cinemas on Wednesday 14th October 2015. The film will be shown for the first time in a new sing-a-long version.

The surviving Pythons Terry Jones, Terry Gilliam, Michael Palin, Eric Idle and John Cleese have recorded a special introduction to play before the film. Audience members are being encouraged to dress up as characters from the film. Sony and Park Circus will also be launching a dedicated interactive social media campaign in the lead up to the release.

Generally considered the Brit comedy troupe’s first “proper” film (the earlier And Now For Something Completely Different was essentially a compilation of sketches), Holy Grail parodies the legend of King Arthur and his quest for the Holy Grail. The film was also the basis for the Emmy-winning 2005 musical Spamalot. It was a success on its release in 1975, becoming the top grossing British film of that year in the U.S. Original Python member Graham Chapman (who died of cancer in 1989) played King Arthur in the film, as well as the voice of God.

The film will also be released internationally by Park Circus and in the U.S. by Rainbow Releasing. Sony Pictures Home Entertainment will release a blu-ray in the fall.