*The original Alien movie, released in 1979, evolved from a script by Dan O’Bannon and Ronald Shusett called They Bite! Thankfully, the writers came up with a much stronger title for the second draft: Star Beast.

*Alien's eponymous creature, designed by Swiss artist H R Giger, was a parasitic killing machine which used humans as unwilling hosts for its lethal offspring. Its unique physiognomy gave it extraordinary defensive and offensive capabilities: acid blood, a scorpion-like tail, an impenetrable exoskeleton, striking inner jaw, and the ability to survive in zero atmosphere.

*In addition to the characteristics of the fully-grown alien, the creature has an extraordinary complex and efficient life cycle: located in a 'hive' built from bodily secretions, the 'Queen' gives birth to dozens of eggs, each containing a 'facehugger' which latches onto the face of its victim, laying an alien embryo which ultimately bursts out of the body of its unwilling host. The creature matures quickly, growing to adulthood in a matter of hours.

*The first Predator movie, released in 1987, grew out of a script by John and Jim Thomas entitled Hunter. It was directed by John McTiernan, who later made such smash hit action films as Die Hard, The Hunt for Red October, and Die Hard: With a Vengeance.

*Ridley Scott had made only one film (The Duelists) prior to making the original Alien. James Cameron, director of the sequel Aliens, had also made only one film previously: 1984's The Terminator.

*Since appearing together in the original Predator, Arnold Schwarzenegger and Jesse Ventura have both been elected state governors. Ventura was elected governor of Minnesota in 1998; Schwarzenegger became governor of California in 2003.

 *The original Alien won a special Oscar for H R Giger's conceptual designs. The sequel, Aliens, was nominated for seven Academy Awards, including a Best Actress nomination for Sigourney Weaver as Ripley.

*A 'director's cut' of Alien was released theatrically in late 2003. Although technically shorter than the original version, it contained several scenes missing from the 1979 version, and featured enhanced sound and special effects.

*The Alien Quadrilogy, a critically-acclaimed DVD box set of all four Alien films, included never-before-seen versions of Alien3 and Alien Resurrection.  It remains one of the best-selling box sets ever.

*Bill Paxton was the first actor to cross over between the Alien and Predator films, appearing in both sequels Aliens and Predator 2.

*In 1990, Dark Horse Comics published the first official crossover between the Alien and Predator franchises, a twelve-issue comic book series entitled Aliens vs Predator. Issue #1 became the best selling independent comic book of all time.