Actually, this fact is mostly false.
But don't worry, it's a common mistake.
C.S. Lewis and J.R.R. Tolkien were in a writing club called the Inklings with one other famous author, Roger Lancelyn Green, who wrote The Knights of King Arthur's table.
C.S. Lewis came to Roger after a meeting with his manuscript and the question of whether or not he should publish it.
He had previously shown it to J.R.R., who had read it and said that it wasn't much good.
Roger read it and disagreed, giving C.S. enough confidence to publish it.
Without Roger Lancelyn Green, we may not have the spectacular series that is The Chronicles of Narnia today.