Obsessed star Idris Elba struggled with some scenes in the new romantic thriller - because he couldn't take his eyes off co-stars Beyonce Knowles and Ali Larter.

The British actor plays Beyonce's husband in the movie and Larter his smitten, psychotic secretary - and Elba admits he was so taken by the beauty of his co-stars and their nasty fight scenes, he'd forget cues and lines.

He explains, "I'm watching Beyonce and Ali go at it, being catty to each other, (and then someone would say) 'Idris, it's your line.' 'Oh, my God, yeah, sorry. Now where am I?'"

He admits working with the two beauties was like being given the keys to two luxury sports cars for the day: "They said, 'By the way, we're thinking of going to Ali Larter and Beyonce.' It was like being given the keys to a Ferrari and a Lamborghini and saying, 'You can have these for all of 24 hours. All yours. But you have to give them back.'

"Those women are beautiful and also very nice people."

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(This news article provided by World Entertainment News Network)