Ridley Scott is now planning up to four Prometheus films, with the final instalment linking up to the events of his classic 1979 space horror Alien, the veteran film-maker has said.

Interviewed for German site FilmFutter, Scott confirmed that plans to eventually connect the two space sagas and explain the origins of the hideous xenomorph extraterrestrials remained intact, but suggested his upcoming sequel to 2012’s Prometheus would expand rather than contract the narrative.

“It won’t be in the next one,” said the British film-maker. “It will be in the one after this one or maybe even a fourth film before we get back into the Alien franchise.”

Prometheus was originally billed as a film “sharing strands of Alien’s DNA”, but only a prototype version of the xenomorph ultimately appeared on screen. The space thriller instead focused its attention on the Engineers, a race of human-like beings who may have created life on Earth, but ultimately failed to explain very much about them.

Scott said “the whole point” of Prometheus was “to explain the how and why of the creation of the Alien itself”. He added: “I always thought of the Alien as kind of a piece of bacterial warfare. I always thought that that original ship, which I call the Croissant, was a battleship, holding these biomechanoid creatures that were all about destruction.”

To complicate matters a fifth Alien film, from District 9 director Neill Blomkamp, is also moving forward, though it is thought Prometheus 2 will arrive first on our screens. The sequel is set to debut in 2017, so if the final two movies arrive in 2019 and 2021 (based on a reasonable gap of two years between films), Scott would be at least 83 by the time the saga is finally complete.

The Gladiator director’s next movie in cinemas also takes place beyond Earth’s borders. The space drama The Martian, starring Matt Damon as an astronaut left stranded and alone on the red planet, debuted at the Toronto film festival earlier this month to positive reviews. Also featuring Jessica Chastain, Kristen Wiig, Jeff Daniels, Michael Peña and Chiwetel Ejiofor, it hits UK cinemas on 30 September and arrives in the US on 2 October.