Ian McDiarmid was 59 in Star Wars: Episode III - Revenge of the Sith when he played the character 'Chancellor Palpatine / Darth Sidious'.
That was over 19 years ago in 2005.
Today he is 79, and has starred in 36 movies in total, 9 of those since Star Wars: Episode III - Revenge of the Sith was released.
In Star Wars: Episode III - Revenge of the Sith, I think Ian McDiarmid looks: