Caption: Gerard Butler and other Hollywood stars have adopted the bracelets despite claims they are mere lucky charms without any scientific or medical benefit.
It's the latest must-have accessory for the world's biggest stars and it costs just £20.
Robert De Niro, David Beckham, Gerard Butler, Demi Moore and Kate Middleton have all taken to wearing 'mystical' black silicone wrist bands – which they believe will boost their performance.
The Power Balance bands incorporate a hologram which its manufacturer claims is 'infused with healing and restorative powers'.
The bands are meant to enhance the body's positive frequencies and block out negative ones from devices such as mobile telephones and radios.
Sports stars including Beckham, Real Madrid's Cristiano Ronaldo, basketball legend Shaquille O'Neal and Formula 1 racer Rubens Barrichello have been wearing the bracelets at work and play.
Now Hollywood stars have also adopted them despite claims they are mere lucky charms without any scientific or medical benefit.
The bands are the brainchild of two brothers Josh and Troy Rodarmel, who invented them on their kitchen floor in Orange County, California, three years ago.
Josh, 28, said: 'Everything in nature has a set frequency. The body has a frequency and things which cause negativity to the human body – like cellphones and radiowaves – break down its natural healing frequency.
'My brother and I worked out a way of putting good frequencies into our holograms so they balance out the body, making it stronger and more flexible.
'The frequencies embedded in the holograms clear pathways and lead to maximum energy flow.
'It works in different ways for different people. Athletes say they can last longer on the field, that they have better balance and that their muscles recover quicker.
Non- athletes say that it works for them, too, giving them extra boost off the field, in many areas of life including the office and in the bedroom.'
High-profile endorsements have sent sales soaring and they are expected to top £10 million this year. David Beckham, 35, who was recently dropped from the England national football team because of his age, is believed to have discovered the bracelets while watching the LA Lakers basketball team.
Observers have questioned whether the player may be using the bands to help prove Fabio Capello, the England manager, wrong.
A source close to the star said: 'David has no intention of retiring. He is working hard to get back to peak fitness.
And he will use everything within his disposal to do that. 'So he is using bracelets. So what?
He will do anything it takes to gain a professional edge.' Critics claim, however, that the bracelets are nothing more than good luck charms.
Dr Richard Vautrey, deputy chair of the British Medical Association's GP committee, said: 'There is no evidence at all that these bracelets would have an impact on performance in the way described.'