Mark Hamill calls Star Wars return 'a gift'

"It was certainly unexpected. I already had a beginning, middle and end. I never thought we'd come back," he told the BBC's Lizo Mzimba.

"To go on to those sets that evoked so many memories. It is just astonishing."

He added that Harrison Ford was recovering well after breaking his leg on set in June.

"I was not on set. It was really terrible but I hear he's doing really well. It will take more than that to stop Harrison Ford," said Hamill, who was speaking on the red carpet of the UK premiere of Guardians of the Galaxy.

The 62-year-old starred in the three original Star Wars films, the first of which was released in 1977.

When the franchise was revived in 2002, the Luke Skywalker character was only seen as a baby in Revenge of the Sith (Episode III).

The new film, which only has the working title Episode VII so far, is due to be released in 2015.

The casting is a mix of original actors, including Ford as Han Solo and Carrie Fisher as Princess Leia, and new faces to the Star Wars universe, such as Oscar winner Lupita Nyong'o and Domhnall Gleeson, whose characters have yet to be named.

Speaking about returning to his biggest screen role with Fisher, Hamill said: "It was fantastic. Again - I thought even if they did a third trilogy, we wouldn't be involved, because it is really about the new generation of characters.

"We are just there to lend our support and grow contractually obligated beards."

He added that the new generation of actors brought in by director JJ Abrams were impressing him.

"These kids - they are not kids - but they are so talented. They are also diverse. There are people I recognise like Andy Serkis and new people that I've never seen before like Daisy Ridley.

"But they are so good. I'm thinking of asking them for advice. I don't want to give any myself!"