"I was lucky to spend many happy hours with Leonard socially and in front of the camera. The caliber and serious commitment of his work on 'Star Trek' was one of the things all of us on 'Star Trek: The Next Generation' sought to match and be inspired by. His work will not be forgotten," Patrick Stewart, who played Captain Jean-Luc Picard on "Star Trek: The Next Generation," said in a Facebook post.
"He was a talented actor, director, poet and photographer. But his most enduring quality was his kindness and his desire to make you the most you could be. Like everyone who knew or knew of him, I will miss him," actor Steve Guttenberg, who starred in the Nimoy-directed blockbuster comedy "Three Men and a Baby," said in a statement.