"Even if you've seen all the films, once you pick up the book again, you're back in the author's world," he says. "I thought that the films wouldn't bleed into the literary work but whenever I think of Gandalf, I just think of Ian McKellen, as it was such a rich and perfect interpretation, which has changed and developed our universal view of the character."
Along with the striking countryside near his home in Dartmoor in rural Devon, New Zealand's distinctive landscapes have had the most significant impact on Lee's contributions to Beren and Luthien.
"I saw a lot of the New Zealand countryside as we were searching for sites to shoot in, so I got to trudge around the fiords and the mountains. I'm sure that some of that has fed back into it but it's also very beautiful where I live.
"It's just like how I imagine the Shire would look, with the rolling hills and national parks. I've lived down here since 1975 and I've done a lot of drawing of the local area, so the landscape has kind of been absorbed into me."
After releasing his second book, Castles, through Tolkien's publishers Allen and Unwin in 1984, Lee was approached by editor Jane Johnson about taking on an illustrated edition of The Lord of the Rings.
There was initially considerable resistance to the idea - it didn't see the light of day until 1992, which marked the 100-year anniversary of J.R.R.Tolkien's birth. Lee says it wasn't until then that it was thought appropriate to do something a bit different.
"So I did some samples and some little drawings of the characters, which were sent to Christopher Tolkien. He approved the look of the characters and I then started work. I did 50 drawings for the centenary edition and after that I did The Hobbit as well."
The third of Tolkien's four children, Christopher has acted as his father's literary executor since his death in 1973. Described by J.R.R. himself as "my greatest critic and collaborator", he has compiled and edited titles such as The Silmarillion, The History of Middle-earth and 2007's The Children of Hurin, which, like Beren and Luthien, included several illustrations by Lee.
"When I was doing The Children of Hurin, I went out to Christopher's house in France to show him the drawings and to get his feedback," recalls Lee. "He's a very good person to work with because he's intensely passionate about the work and how well you are presenting his father's work. So if you've got his blessing, then you have won half the battle."
With the first version of Beren and Luthien dating back to 1917, J.R.R. Tolkien reworked the story on numerous occasions in both prose and poetic form. Posthumously included in 1977's The Silmarillion, Christopher has included all the various iterations in the recently-published standalone volume.
Along with The Children of Hurin, Beren and Luthien is a part of a trio of Lost Tales that remained unfinished after Tolkien's death. However, as he states in his preface, the now 93-year-old Christopher Tolkien is unlikely to produce a completed volume of The Fall of Gondolin.
"J.R.R. Tolkien did have these three stories in mind for further development, which were all distinct sagas within the whole story of The Lord of the Rings," says Lee. "But I think this might be the end."
Beren and Luthien
By JRR Tolkien; edited by Christopher Tolkien and illustrated by Alan Lee
HarperCollins, $50
