According to the article, he was Count Dooku in two Star Wars films. Must’ve been the prequels - I only watched the first, and did not like it so skipped the rest.
https://www.youtube.com/watch?v=GaXHDpCe-KI
https://www.youtube.com/watch?v=eYT3ctPuVRw
There are a couple of his scenes from the movies (he was in Episodes II and III). Only fitting such an iconic, legendary actor would appear in the Star Wars Movie Series. He has, as always, an excellent performance in this character role - you might enjoy the movies just to see him. These movies were actually being released within the same time period as the Lord of the Rings movies so he was playing an iconic villain in two different series of highly popular films.