The Alien film we never got to see because of Alien vs Predator

Forget The Avengers. Forget Deadpool and Wolverine. 20 years ago, Alien vs. Predator gave film fans the ultimate crossover event. Two lethal extra-terrestrial killing machines went head-to-head in a colossal battle, with humanity caught in the middle and helpless to do very much about it.

Two decades on, Alien vs. Predator remains something of a divisive film — not helped by its hated sequel Aliens vs. Predator: Requiem — and both franchises have moved on to new directions. Predator had a great prequel movie, Prey, in 2022 and Fede Álvarez is taking Alien back to its horror roots with Alien: Romulus — out this week and set between Alien and Aliens.

But Alien vs. Predator actually had a more profound impact on the Alien franchise than it might initially seem. It effectively put an end to a sequel that would've united the massive filmmaking minds behind the first two movies — Ridley Scott and James Cameron.

In a 2006 interview with Ain't It Cool News, Cameron explained that "Ridley and I talked about doing another Alien film" prior to AvP. Cameron would've been writer-producer, with Scott behind the camera. But the face-off movie put a spanner in the works of Cameron's plans, souring the potential of the man behind Aliens returning to the franchise.

He added: "I started working on a story, I was working with another writer and Fox came back to me and said 'we've got this really good script for Alien vs. Predator' and I got pretty upset. I said: 'You do that you're going to kill the validity of the franchise in my mind.' Because to me, that was Frankenstein Meets Werewolf. It was Universal just taking their assets and starting to play them off against each other."

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It's fair to say that Cameron wasn't keen on the idea of combining these two franchises, though he did confess that Paul W.S. Anderson's movie was "actually pretty good" once he actually saw it. As for Scott, he told Empire in 2012 that he hadn't watched either of the crossover films. He said: "I couldn't quite take that step."

Watch: Ridley Scott talks to Empire Magazine in 2012

20th Century Fox, as it was known before its merger with Disney, decided to pursue the Alien vs. Predator movie in the early 2000s, inspired by a neat little Easter egg inserted into the 1990 sequel Predator 2. There was an alien skull among the hunting trophies on the Predator ship. Dark Horse Comics had previously published an Aliens versus Predator series, starting in 1989.

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Interest in a crossover film was growing at the studio level. Predator co-writer Jim Thomas described it as "a good idea that will probably never happen", while Peter Briggs — who would go on to write Hellboy — penned a spec screenplay. Numerous writers subsequently took a shot at it during the 1990s, including future Purge franchise creator James DeMonaco.

Fox was focused on Alien: Resurrection during the 1990s, but they were impressed when Paul W. S. Anderson came along with a pitch for an adaptation of the comic book story. Anderson worked with writer Shane Salerno — these days, interestingly, working with Cameron on the Avatar sequels — to punch the story into shape for Anderson to direct, set in the present day and with careful attention to the continuity of the original Alien, which took place in the year 2122.

With Fox so firmly in the crossover camp, Cameron and Scott's concept for an Alien sequel faded away into the ether. Alien vs. Predator was a box office hit to the tune of $177m (£139m), but the sequel arrived three years later to lesser box office and poisonous reviews. The crossover era was over.

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Meanwhile, Scott's ideas about exploring the origins of the xenomorph as part of his discussions with Cameron weren't gone forever. They resurfaced in 2012 when Scott directed Prometheus, ushering in a more philosophical direction for the franchise. It divided both critics and audiences and, following sequel Alien: Covenant, it doesn't seem very likely we'll be seeing any more from that corner of the franchise.

It's equally unlikely that we'll ever see Scott and Cameron work on another Alien movie together. Scott is 86 years old and focusing on the projects he's most passionate about — his next movie is Gladiator II — while Cameron has essentially pledged the next decade of his life to Avatar.

Both men are seemingly very happy with the current direction of the Alien franchise though. Fede Álvarez told The Hollywood Reporter that both men had seen the movie during the editing stage, with Cameron reporting that he "loved it" and Scott describing it as "f***ing great". That's a big vote of confidence from two of the greatest filmmakers alive today.

Fox was excited to bring two titans together for Alien vs. Predator, but that somewhat denied audiences the collaboration they really wanted to see: Scott and Cameron.

Alien: Romulus is in UK cinemas from 16 August, while Alien vs. Predator is streaming on Disney+.