Gwyneth Paltrow thinks Beyonce Knowles is the best performer in the world.

The 'Iron Man' actress is in awe of her friend's work ethic and believes none of her contemporaries can compare.

She told US Vogue: “When she is working onstage, she has more power than any woman I’ve ever seen. She would never say it and has never said it, but I feel she knows with every fiber of her being that she is the best in the world at her job.”

Paltrow is also impressed with how the 'Halo' hitmaker – who gave birth to her first child in January 2012 - juggles motherhood and her career.

She added: “Blue was sleeping in her arms, across her body, and B was listening back to what she had been working on. I thought, ‘This is how you do it. You do what you love with who you love included.’”

Beyonce and Paltrow's husband's Jay-Z and Chris Martin are also close friends and Martin has previously revealed he thinks their friendship is "hilarious" and they get on well because they can identify with one another.

He said: "Yes, it is hilarious [our friendship]. What's the common denominator? Well, underneath he probably feels a bit like me and I probably feel a bit like him."

Paltrow believes her husband and the '99 Problems' hitmaker get on well as they "balance" one another.

She said: "They balance each other out. Chris and I are like Jay and Beyonce; two paranoid ironists and two calm grounded people."

Martin added: "There you go, you've got the answer. We balance each other out."