Stellan Skarsgård was 18 in Den byxlöse äventyraren when he played an uncredited character.
That was over 53 years ago in 1971.
This was his first recorded movie acting credit (although may not technically be his first actual acting role).
Today he is 72, and has starred in 141 movies in total, 140 of those since Den byxlöse äventyraren was released.
In Den byxlöse äventyraren, I think Stellan Skarsgård looks: