Now this must have been torturous!

The moment in The Empire Strikes Back when Darth Vader tells Luke Skywalker, “I am your father,” is one of cinema’s most epic plot twists. But did you know that the cast literally had to keep it secret for over a year?!

Mark Hamill recalled that time on Twitter over weekend just a few days after the film’s 40th anniversary.

Apparently, it was originally written that Obi-Wan had killed Luke’s father. Thank God they didn’t choose that ending!

The epic moment is one of the best twists in film history. Good for Mark for keeping it secret!