Star Wars: Episode V – The Empire Strikes Back

With the movie often touted as one of the best sequels in Hollywood history, it'll come as no surprise to hear 'Star Wars: Episode V – The Empire Strikes Back' dominated the box office.

With an initial budget of $18 million – before it ballooned to $33 million – the sci-fi flick stayed at the number one spot at the box office for 18 weeks, before leaving the silver screen having grossed about $550 million.

The 1980 picture is probably best-remembered for including one of the biggest plot twists in cinematic history, in which Darth Vader reveals to Luke Skywalker (Mark Hamill) that he is his father.

Looking back on the twist, Hamill admitted it was "agony" keeping the detail a secret from the rest of the cast, who had been given a fake script that read 'Obi-Wan killed your father'.

He recalled: "The cast and crew first learned of it when they saw the finished film.

"When we shot it, Vader's line was 'You don't know the truth, Obi-Wan killed your father.' Only [director] Irvin Kershner, George Lucas, and I knew what would be dubbed in later. Agony keeping that secret for over a year!"