An animated graphical sequence of a Gordon's and tonic mixed in four "acts" will be projected onto the stage curtain.
Twenty-six UK theatres owned by the Ambassador Theatre Group, yet to be finalised, are expected to screen the ad from this month. According to a spokesman, it is the first time ATG has allowed a digital animated projection of a brand.
It will not be shown at family-oriented shows or pantomimes, according to Mike Hope-Milne, the enterprise director at Pearl & Dean.
Hope-Milne said: "The audience is bang on their target market of 35-plus ABC1 people" and said it was important the ad felt theatrical.
The spot is designed to reinforce the new positioning of Gordon's as the first drink of the evening. It includes the fresh strapline "Shall we G&T started?".
Gordon's ads will also appear on ticketing websites and the Diageo brand will offer discounts at ATG theatre bars. The activity has been handled by direct and digital agency TMW.
As part of the same deal, media agency Carat has booked the brand's new TV ads, featuring actors Philip Glenister and Emilia Fox, against arts programming in Pearl & Dean's portfolio of cinemas – Apollo, Empire, Showcase and Everyman.
Pearl & Dean estimates the ads will be seen by up to 17 million cinema and theatregoers over the year-long deal, which Hope-Milne put at six figures.