As much as any movie in Gerard Butler's career, '300' stands as one of his most recognisable - and his line, "THIS IS SPARTA!", is up there as one of the great one-liners of modern movie history.

It's so ridiculous, so brazenly over-the-top, that you can't very well not say it in a loud voice and follow it by attempting to kick someone square in the chest. It's like trying to do Don Vito Corleone's voice from 'The Godfather' without scratching your face, or Hannibal Lecter's "fava beans and a nice Chianti" without doing the air-sucking thing.

Anyway, while it might seem like it was completely planned and thought-out by Gerard Butler, it actually wasn't at all. As he told GQ in their delightful video series of actors and roles, it actually caused a bit of a chuckle from the fellow actors - Michael Fassbender among them.

"I had done quite a few takes and most of them were... (quietly) 'This is Sparta'. And it's part process and part insecurity, maybe. And I go, 'Can I just try another?'" Sure enough, that's the take that's used in the final movie, but on the set, it made everyone laugh. "And I turn around and all my army are literally like this, (imitating laughs behind hands), and I go up to Zack and I go, 'That was too much?' And he goes, 'Yeah! But it was awesome!'"

To be fair to Butler, nobody in '300' was playing it remotely subtle, not even Michael Fassbender with his infamous "...then we will fight in the shade..." line about arrows blotting out the sun. It's a silly, silly movie - so why not play it like it's actually one?

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