Who was the other well known writer that Tolkien friends and what literary where they both a part of?

The other well-known writer that J.R.R. Tolkien was friends with was C.S. Lewis.

They were both part of the Inklings, an informal literary discussion group that met regularly in Oxford, England, from the 1930s to the 1950s.

The Inklings were known for their shared love of fantasy, mythology, and Christian faith, which heavily influenced their works.