In addition to being one of the highest grossing films of the 1980s, Back to the Future’s movie poster is one of the decade’s most recognizable pieces of pop culture memorabilia. Drew Struzan’s image of Marty McFly looking at his wristwatch as he climbs out of his DeLorean time machine has reached iconic status, but it’s not the only poster that was considered.

Before Universal Pictures decided on using Struzan’s work, a number of other potential posters were reviewed, and rejected. Now a never-before-seen Back to the Future poster contender that was recently discovered will go up for auction.

The unused poster was discovered at Lonsdale Advertising in England, when a former employee was digging through the agency’s old archive and collection. The movie one-sheet features a black-and-white George McFly (Crispin Glover) and Lorraine Baines (Lea Thompson) looking rather surprised as their future son falls into the image in full color. The iconic DeLorean is featured in the poster, too—though it’s hidden in the background. It also features a tagline that wasn’t used for the final film: “Marty’s Parents Were Destined To Meet in 1955. Until Marty Dropped in From The Future.”

The never-before-seen movie poster will go up on the auction block next month at Ewbank's. It’s estimated to sell for between £200 and £400 (about $300 to $600).

[h/t /Film]