Christopher Masterson was 7 in Hiroshima Maiden when he played the character 'Timmy Bennett'.
That was over 36 years ago in 1988.
This was his first recorded movie acting credit (although may not technically be his first actual acting role).
Today he is 44, and has starred in 21 movies in total, 20 of those since Hiroshima Maiden was released.
In Hiroshima Maiden, I think Christopher Masterson looks: