Lena Headey has joined the cast of the adaptation of Frank Miller's graphic novel 300, Variety reports.

The film will chronicle the battle of Thermopylae, in which King Leonidas and 300 Spartan warriors took on the great Persian army. Their bravery is credited with uniting Greece and helping along the development of democracy.

Gerard Butler (Reign of Fire) will play Leonidas, whilst Headey (The Cave) will play his queen.

Zach Snyder (Dawn of the Dead) is directing the movie, which he also wrote along with Kurt Johnstad. Michael Gordon wrote a previous version of the screenplay.