Rumors of Phoenix's involvement surfaced in September when the Vulture blog reported the actor was said to be Eastwood's top choice to play Clyde Tolson who was the associate director of the FBI from 1947 to 1972.
Filmmakers are "in the process" of signing contracts with DiCaprio, Eastwood told the news agency.
Of Hoover, Eastwood said, "He was a very complex person. The homosexual aspect is just one of many. I would say that's the least of his problems. But he was also very clever, whether rightfully or wrongfully, he was very clever about keeping himself in a certain position in life, so it is an interesting study...He is a fascinating character, and I think I am the right person to do it , not because I knew him or anything, but I did grow up with him."