Mark Hamill, Luke Skywalker himself, has celebrated the annual May the Fourth Be With You Star Wars Day celebrations with something very special: channelling his dark side to prank fans.

As part of Lucasfilm’s Star Wars: Force for Change campaign, fans were invited to what they thought would be a simple video to remember the best scenes in the space saga’s 40-year history. But, as Hamill says, “it’s a trap!”

As they re-enact the most memorable moments from the films in front of a blue screen, Hamill creeps up behind them or appears in disguise. And his reveal to shocked fans is perfect: he greets one with a handshake (with his missing hand), and performs a horrifyingly good Vader impression for another.

Let's just hope the fans didn't find Hamill's entrance too terrifying. As a wise Jedi once said: “Fear is the path to the dark side.”

And for your chance to win a lunch with Hamill himself (or a night at Skywalker Ranch, a visit to the set of the upcoming Han Solo movie, or a trip to The Last Jedi premiere), all you need to do is donate to Force For Change, which benefits UNICEF and Starlight Children’s Foundation.