Ridley Scott says there will be a 'Prometheus 4'.

The 77-year-old director made the classic sci-fi horror movie in 1979 as a prequel to 'Alien' but it took off in its own right and has now revealed to fans - who were hoping that 'Prometheus 2' would finally combine the two stories when it's released in 2017 - that there will be two further sequels.

Ridley said: ''Prometheus has its own story to tell before it eventually ties into the movie that started it all...it won't be in the next one. It will be in the one after this one or maybe even a fourth film before we get back into the 'Alien' franchise.''

'Prometheus 2' is based on two scientists - played by Noomi Rapace and Logan Marshall-Green - who find a clue to mankind's origins on Earth.

And the acclaimed director - whose other recent credits include 'The Martian' and 'Exodus: Gods and Kings' - insists it is too early in the timeline to bring the stories together.

He told Colider: ''The whole point of it is to explain the 'Alien' franchise and to explain the how and why of the creation of the Alien itself.''

'Prometheus 2' hits cinemas May 2017.