Idris Elba worried about his ''terrible'' American accent.

The 'Pacific Rim' actor was relieved to learn he could retain his British accent in the new Hollywood blockbuster directed by Guillmero del Toro, because he can't quite seem to capture the voice of an American.

He quipped: ''If you come from England or Australia and you want to come to America to work, it's a good idea that you learn an American accent. Don't do what I did and show up with a really terrible accent and not work for four years.''

The star says his 'Pacific Rim' character - an army commander - will have a British accent, but not the east London dialect he possesses.

He explained to 'The Late Show with David Letterman': ''English, but not as cockney. My character speaks a bit more like [Shakespearean actor] Kenneth Branagh.''

Elba also revealed he was shocked to discover that the producers of his first ever US TV role, 'Space Precinct', had dubbed his voice in the series - with a German actor.

He said: ''I did an American accent for it so it must have been really terrible. I heard it later and said, 'That's not me!' And they said, 'Yeah, we used the guy who dubs your voices in other TV shows.'

''I was like, 'The German black guy? That's his voice?' So even in Germany there's a guy with a better American accent than me dubbing my voice.''

As well as 'Pacific Rim', Elba will reprise his role as Heimdall in superhero film 'Thor: The Dark World' later this year.