Tom Courtenay was 23 in Private Potter when he played the character 'Pvt. Potter'.
That was over 62 years ago in 1962.
This was his first recorded movie acting credit (although may not technically be his first actual acting role).
Today he is 87, and has starred in 53 movies in total, 52 of those since Private Potter was released.
In Private Potter, I think Tom Courtenay looks: