LONDON – No one was more surprised by Mark Hamill’s lack of screen time in Star Wars: The Force Awakens than Hamill himself.

When he first got the script for the J. J. Abrams’ blockbuster, which has raked in $2 billion at the global box office since its release last year, he flipped through the script looking for his scenes. And flipped, and flipped, and flipped some more.

“I thought it was a great surprise, but I don’t think they prepared me correctly,” a jovial Hamill told a rapt crowd Friday on the opening day of Star Wars Celebration Europe, a massive Star Wars fan convention being held this year at the ExCel Center in London.

“I went to training and lost all this weight and I thought I must be doing something physical if they’re sending me to the gym twice a week.”

As fans now know, Hamill has less than a minute of screen time in the film’s final scene, in a shot which he wordlessly turns, removes his hood and looks at Daisy Ridley’s Rey.

“It’s the most elaborate entrance in the history of show business! And then it’s over,” said Hamill. “I thought it worked very well. I want to do movies now where I don’t talk, I get second billing and I’m in the movie for 30 seconds.”

But surely he’ll be putting all that training to use for the just-wrapped Star Wars: Episode VIII, coming out next year? Surely?

To the mild disappointment of some fans, Hamill wasn’t about to dish on Episode VIII spoilers. The filmmakers’ secrecy – which included scripts delivered on iPads secured with complex passwords, and call sheets with actors referred to by numbers instead of names – isn’t malicious, Hamill said. “They’re not doing it to annoy you, they just want the surprise to be in the movie theatres and not on the Internet. You don’t want to know what you’re getting for your birthday!”

During a rollicking one-hour question-and-answer chat with a huge crowd packed into one of the convention centre’s largest halls, Hamill talked about his upbringing, his return to voicing the Dark Knight’s nemesis the in the upcoming animated feature Batman: The Killing Joke (“It’s not for kids. It’s really mean and nasty,” he said) and how he hated the name Luke Skywalker.

In George Lucas’s original script, Hamill explained, the character’s name was the much cooler-sounding Luke Starkiller, but was changed after filming had already begun.

“I said, ‘Luke Skywalker? It sounds like Luke Flyswatter! I hate that name! I want to be Luke Starkiller!’ ”

But shooting the first Star Wars was an endlessly fun experience, he said.

“Even a scene as serious as Ben Kenobi getting cut down, we were laughing. We were laughing all the time,” he said. “It was goofier than hell.

“You’re sitting next to Alec Guinness – one of the most venerated guys in the English-speaking world – and this guy in an eight-foot dog costume.”

While Hamill said he wasn’t going to dish on spoilers, one fan sneakily asked him Rey’s last name, with the prevailing theory being that the character is Luke’s own daughter.

“Very clever,” Hamill said. “That will happen to me, I’ll get bewildered and blurt out inadvertent spoilers.”

It’s the sort of thing that comes with age, and Hamill realizes how different he and the rest of the original Star Wars cast look now, especially to young kids who only recently saw the original trilogy for the first time.

“They look at me and they’re aghast,” he said. “ ‘What happened to this guy! They really let themselves go.’ ”

Whatever fate may befall Luke Skywalker in Episode VIII, Hamill is keenly aware how lucky he’s been.

“I never expected to be in anything that would be remembered, or at least remembered fondly,” he said. “You’re more like family than fans.”