Roddy McDowall was 40 in Beneath the Planet of the Apes when he played the character 'Cornelius (archive footage) (uncredited)'.
That was over 54 years ago in 1970.
In 1998 he died aged 70, starring in 166 films in his career, 109 of those after Beneath the Planet of the Apes was first released. If he were alive today he would be 95.
In Beneath the Planet of the Apes, I think Roddy McDowall looks: