Forbidden Planet has been providing Brits with their comic books, sci-fi novels and pop culture merch for 40 years now – and tomorrow the cult entertainment chain is holding a birthday bash to celebrate the occasion.

Stores in Birmingham, Bristol, Cambridge, Coventry, Croydon, Liverpool, London, Newcastle and Southampton will be giving the first 40 customers of the day a goody bag, with giveaways of books, badges and other goodies running throughout the day.

Shoppers will also be able to snag a special souvenir magazine featuring four decades of Forbidden Planet guests (also available online as a free download) and, until it runs out, a nice slice of birthday cake. In addition, the company has launched a range of Fortieth Anniversary merchandise, including a varsity jacket and a Rick & Morty homage to Forbidden Planet’s iconic original store poster.

Forbidden Planet’s flagship London Megastore is also welcoming Black Library authors Dan Abnett, David Guymer and Peter Fehervari, who will be signing copies of new Warhammer 40,000 novels The Burden Of Loyalty and Servants Of The Machine God from 13:00 – 14:00. Meanwhile, the firm’s Newcastle store is hosting an exhibition of photographs of signing guests from 1978 to 1989.

Speaking of guests, Forbidden Planet has played host to plenty of geek culture royalty since its first store opened on London’s Denmark Street back in 1978 – here’re a few folks you might recognise from the firm’s new photo archive:

Stan Lee, April 1987

Terry Pratchett, November 1988

Douglas Adams, August 1982

Neil Gaiman, October 1988

Stephen King, May 1983.