Mark Hamill has teased the Luke Skywalker that fans will see in 'The Last Jedi' is a character haunted by the decisions he has made and the tragedies that have happened in his life.

The 68-year-old actor reprises his role as the Jedi Master in the upcoming 'Episode VIII' and he admits Luke's sole line in 'The Force Awakens', ''I know only one truth, it's time for the Jedi to end'', gives a huge insight into the mental state of the character.

Hamill admits the evil actions of Luke's nephew Ben Solo - who became Kylo Ren (Adam Driver) and murdered the new Jedi Order Luke was training - that occurred between 'Episode VI: Return of the Jedi' and 'Episode VII: The Force Awakens' have caused a profound change in Luke's beliefs but he is adamant that he has not turned to the Dark Side like his father Anakin Skywalker did before him when he became Darth Vader.

Speaking to Disney Rewards magazine, Hamill said: ''I don't think Luke's fundamental personality has changed [over the years], except that he is older and his life experiences have shaped his outlook the same way they do for all of us. The biggest challenge for me was actually in the time between 'Return of the Jedi' and 'Star Wars: The Force Awakens'. I had to know what had happened to Luke during those years. I had to glean decades of backstory from the script. And some of it I had to make up for myself. I had to know what he went through during that time. It's not important to the storyline for this film, but I did discuss some of my thoughts with Rian Johnson to make sure I wasn't coming up with anything in my personal backstory that would affect Luke's portrayal in this film. In 'The Force Awakens', Luke has lost confidence in his ability to make good choices. It haunts him to the core. But he hasn't gone to the dark side. This isn't an evil version of him. But it's still an incarnation of the character I never expected. It has pulled me out of my comfort zone. It's a real challenge.''

Hamill has teased that 'The Last Jedi' - which will focus on Luke's relationship with Rey (Daisy Ridley) and her significance in the galaxy - contains several ''jaw-dropping surprises'' and is very proud of the story that he and his castmates, who include John Boyega, Oscar Isaac, Andy Serkis and the late Carrie Fisher, have told.

He added: ''I'm sure this line is a great shock to the audience [to hear Luke say that it's time for the Jedi to end], so you can imagine how I felt! This is a huge change for a character who once represented optimism and hope. It's a radical decision to drop out of everything he's ever believed in. The entire movie is filled with these kinds of jaw-dropping surprises, but you'll just have to see the film itself to discover what they are.''