Rupert Graves was 18 in Mona when he played the character 'Jim Atkins'.
That was over 42 years ago in 1982.
This was his first recorded movie acting credit (although may not technically be his first actual acting role).
Today he is 60, and has starred in 60 movies in total, 57 of those since Mona was released.
In Mona, I think Rupert Graves looks: