Emily Blunt has apologised after joking that she regretted her decision to become an American citizen after watching a Republican Presidential candidate debate which many Americans have branded insensitive and some American TV show hosts have been quick to take offence to.

Emily BluntThe actress has come under fire for saying she regretted her decision to become an American citizen

The actress, who has starred in hits including Into The Woods and The Devil Wears Prada, made the comments at the Toronto International Film Festival.

The Republican Presidential candidate debate had taken place on the same day the mum-of-one she had gone through the official citizen ceremony with her American husband of five years John Krasinski.

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She said: "We watched the [Republican] debate and I thought: ‘This was a terrible mistake. What have I done?’

"I’m not sure I’m entirely thrilled about (becoming an American)."

However, America was quick to defend itself against her comments and particularly angry Fox presenter Anna Kooiman said: "You know what then, why don’t you leave Hollywood, California?

"Let some American women take on the roles that you’re getting because Americans are watching your movies and lining your pockets."

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Blunt has since gone on TV to apologise for her off-the-cuff remark.

She said: "It was so not the intention to hurt anybody or cause any offence, so I really apologise to those that I caused offence.

"It was just an off-hand joke. I think I'll probably leave the political jokes to [talk show] Late Night or something."