Tim Matheson was 18 in Divorce American Style when he played the character 'Mark Harmon'.
That was over 57 years ago in 1967.
This was his first recorded movie acting credit (although may not technically be his first actual acting role).
Today he is 76, and has starred in 101 movies in total, 100 of those since Divorce American Style was released.
In Divorce American Style, I think Tim Matheson looks: