The official 'Star Wars' social media sites are celebrating the 40th anniversary of the release of 'The Empire Strikes Back.' The film made its debut on May 21, 1980, and was an instant classic. Encouraging people to share their experiences with the film with the #ESB40 hashtag, the site released both a new poster for the film, as well as a short video looking back at the making of the iconic movie.

The clip contains behind-the-scenes footage, statements from George Lucas, director Irvin Kershner, and of course, some of the film's cast: Mark Hamill, Carrie Fisher, Harrison Ford Billy Dee Williams, and Anthony Daniels. They promote the movie, talking about what it's all about and how it takes the film franchise forward. It's a real blast from the past, taken from a time before 'The Empire Strikes Back' was even released. 

George Lucas and Carrie Fisher both mention how the movie, despite its sci-fi settings, is a fantasy. It's about good vs. evil, and light vs. dark. All of the cast talked about how it's a much different film than 'Star Wars: A New Hope,' mentioning that while the new film has its moments of comedy, it's also a much darker movie. Ford talks about his strong working relationships with Fisher and Hamill. Hamill, for his part, jokes about demanding proof that Han Solo is pursuing a relationship with Princess Leia. 

The clip also shows behind-the-scenes look at the on-set locations for the shooting of Hoth, the ice planet. "It's almost unreal," says director Kershner, "It's a glacier, it's north, the weather's bad - which is what we want - and it looks like another planet." We also see the sets for Cloud City, where the cast teases the strangeness of the city, claiming it to be unlike anything audiences had seen before. 

You can watch the full video below:

The 'Star Wars' social media sites also posted a new poster, designed by artist Matt Ferguson, featuring Darth Vader looming large with the Empire's vaunted might surrounding the iconic image of Luke Skywalker battling Vader. 

'Star Wars: The Empire Strikes Back' is now available to stream on Disney+.