Brian Cox was 18 in A Knight in Tarnished Armour when he played the character 'Nelson'.
That was over 58 years ago in 1965.
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 164 movies in total, 159 of those since A Knight in Tarnished Armour was released.
In A Knight in Tarnished Armour, I think Brian Cox looks: