That was over 14 years ago in 2007.
Today she is 47, and has starred in 50 movies in total, 22 since 300 was released.
In 300, I think Lena Headey looks:
300 scores 7 out of 10 on The Movie Database.
Lena Headey's first acting role was as 'Young Mary' in Waterland, released in 1992 when she was 18.