LeAnn Rimes has admitted singing 'American Beautiful' on 'Logan Lucky' was the "easiest thing" she's ever done.

LeAnn Rimes

LeAnn Rimes

The 34-year-old star was asked to perform the hit song on the film after director Steven Soderbergh watched her sing the US national anthem at the Indy 500 motorsport event at Speedway, Indiana in May 2014 - and she only needed to belt out the track twice on the set.

She said: "I guess Steven Soderbergh had seen me perform the national anthem at the Indy 500 a few years ago, and when he needed someone to sing 'American Beautiful' for this Nascar race he called me.

"I ended up in Atlanta, where they were filming the movie, and I went down to set and sang 'American Beautiful' twice and that was it.

"It was the easiest thing I've ever done, honestly."

However, the 'How Do I Live' hitmaker was concerned the evening before her performance because she thought she would have to sing the whole eight verses of the patriotic song, before being reassured by the filmmaker.

Speaking on interview show 'BUILD Series', she added: "I actually freaked out when I went to set because the night before they handed me the lyrics and there are eight verses.

"So, I go, 'Woah, OK. So he wants all eight verses?' And his producer was like, 'Oh yeah, he wants all eight verses.'

"I was like, 'Can I talk to him? This can't happen.'

"So I go to the set and I was like, 'There's eight verses, do you want all these?' And he says, 'There's eight verses?' And I was like, 'Thank you, God. He doesn't know there's eight verses.'

"He said, 'No, no, just two of them is good.' "