Your average Christian is going to know who C.S. Lewis is.
Your slightly less average Christian will know who J.R.R. Tolkien is.
A rather odd Christian will know that Lewis and Tolkien knew one another and were members of an Oxford-based club, the Inklings.
It takes a really weird Christian to know that Tolkien was one of the major influences on Jack Lewis's conversion.
Congratulations, you are now a really weird Christian. And if you want to be a fanatic, C.S. Lewis was nicknamed after a childhood neighbor's dog, Jack. (This calls to mind a certain Indiana Jones).
But anyway, to get back to that conversion thing. It's a rather good story. One day, High Anglican Hugo Dyson, Roman Catholic Tolkien, and intellectual atheist Jack Lewis were strolling down Addison Walk. Tolkien and Lewis were talking about their mutual obsession: myths and fantasy. Tolkien was using that medium to get Christianity into the conversation. The incident profoundly shaped Lewis's worldview, and Tolkien's writing. A little while later, Lewis embraced Christianity (oddly enough, on a trip to the zoo; in Surprised by Joy he writes "When we set out to Warnade Zoo, I did not believe that Jesus Christ was the Son of God, and when we reached the zoo I did.")
Tolkien and Lewis remained friends for years, though there was a stumbling block involving The Chronicles of Narnia (and Lewis's friendship with the odd Charles Williams). Tolkien thought the Narnia books were sloppy and inconsistent and wasn't afraid to say so. On the other hand, Lewis was The Lord of the Rings' only fan for years upon years before it was published (not counting Christopher Tolkien). Lewis loosely based the character Ransom (from his space trilogy) on Tolkien. Tolkien returned the favor by giving the ent Treebeard Jack Lewis's booming voice, if not his penchant for "hasty" writing.
Despite their disagreements, when Lewis died, Tolkien wrote: “So far I have felt the normal feelings of a man my age — like an old tree that is losing all its leaves one by one: this feels like an axe-blow near the roots."
I recently discovered this dramatization of the Addison Walk conversation. The acting isn't big-screen, but it's still well worth the time, especially for fantasy fans, or Christians trying to understand fantasy.