Beyonce Knowles has bought her husband Jay-Z the world's fastest road car.

The 'Sweet Dreams' singer treated her rap star spouse to a $2 million Bugatti Veyron Grand Sport vehicle for his 41st birthday, which was on December 4.

The '99 Problems' rapper - who already has a vast car collection, was thrilled with the surprise speedy gift, which Beyonce had to order a year in advance.

A source told The Sun newspaper: "Jay-Z has one of the most enviable collections of bling cars in the world - but even for him the Bugatti is special.

"Obviously the money isn't a factor for Beyonce, but he will be touched that out of everything she could have bought him, she chose something he'll treasure for years."

Jay-Z - who is an ambassador for American motor giant GMC - already owns a Maybach 62S, a Ferrari F430 Spider and a Pagani Zonda Roadster.

But the Bugatti - which has attracted other celebrity customers such as Simon Cowell and Tom Cruise - could be the most impressive yet, with a maximum speed of 255mph.

Money is not a worry to Beyonce and Jay-Z, who were named the highest-earning couple in showbusiness last year, earning $122 million between them from June 2008 to June 2009.

They beat a number of other heavyweight couples, including Brad Pitt and Angelina Jolie, who were worth$51 million, and David and Victoria Beckham, who raked in $44 million.