Mark Hamill reveals struggle to keep Luke Skywalker's parentage secret

Mark Hamill struggled to keep quiet about Luke Skywalker's father being Darth Vader while filming the original Star Wars trilogy.

The 66-year-old revealed on The Graham Norton Show on Friday (15Dec17) he was told the big secret minutes before filming the iconic scene in The Empire Strikes Back in 1980.

He winced as he recalled how difficult it was to keep the fact that Darth Vader the biological father of hero Luke Skywalker from his friends, family and more importantly, his co-stars.

Hamill was handed a piece of paper by director Irvin Kershner, who warned him not to tell anyone about the big reveal.

"(Kershner said) 'If it leaks, we'll know it was you'. He handed me the piece of paper that said, 'I am your father'. I was shocked. I just said, 'Is that true?' He said, 'Search your feelings and we're going to play it like it is true!'" Hamill explained.

"Then I was paranoid... It was way before social media and all that, but I had to keep the secret for like a year-and-a-half. I didn't tell (Carrie Fisher). You know, telephone, telegraph, tell-a-Carrie. Harrison (Ford) and I would test her. If you really wanted to get something out fast, you'd ask Carrie to keep it in her confidence. Then out it would go," he joked.

Hamill revealed that Ford, who played smuggler Han Solo in the sci-fi saga, was furious he had been kept in the dark about Luke Skywalker's parentage, after finding out Darth Vader was his father at the premiere of The Empire Strikes Back.

"So, at the screening, when that happened, Harrison turned to me and said, 'Hey kid, you didn't f**kin' tell me that!'... I was so thrilled (it was out) because I didn't have the burden of that," Hamill laughed.