Kenneth Branagh was 19 in Chariots of Fire when he played the character 'Cambridge Student - Society Day crowd (uncredited)'.
That was over 43 years ago in 1981.
This was his first recorded movie acting credit (although may not technically be his first actual acting role).
Today he is 63, and has starred in 89 movies in total, 87 of those since Chariots of Fire was released.
In Chariots of Fire, I think Kenneth Branagh looks: