The Nov. 22 service was conducted by the dean of Westminster, the Very Reverend Dr. John Hall.
''Fifty years after the death of C.S. Lewis, we assemble to give thanks for his life and work," Hall said during the ceremony. "We celebrate his work as a scholar, as one of the most significant Christian apologists of the 20th century, and as the author of stories that have inspired the imagination and faith of countless readers and film-goers.
"Here are buried or memorialized over 3,000 men and women of our country and of the Commonwealth and of the English-speaking world. Today the name of C.S. Lewis will join that distinguished roll when we dedicate a permanent memorial to him near the graves and memorials of poets and other writers in the South Transept," he said. "As we celebrate C.S. Lewis, so we shall pray that scholars, writers and apologists may be inspired by his example, and that his work will continue to exercise an influence for good on young and old alike."
Among Lewis' works were "The Chronicles of Narnia" series of books and "The Screwtape Letters." The author died in 1963 at the age of 64.