When Cristiano Ronaldo arrives at the Bernabeu Stadium or Kobe Bryant at the Staples Center, chances are a pair of Beats by Dr Dre headphones are wrapped round their head. When Rafael Nadal arrives at courtside or Michael Phelps is trying to concentrate by the pool, they too are shielded from the hubbub by the now iconic out-size earpieces. In five short years since they first appeared in 2008, Beats became first one of the world's most recognizable brands, then the prize in one of the biggest deals in the history of consumer electronics. Apple's impending $3.2 billion buy-out of the firm founded by hip-hop impresarios Dr Dre and Jimmy Iovine may have more to do with the pair's online music streaming service than the headphones. But the pair's marketing genius is a key reason why the tech giant, which has lost a lot of its former street cred on its way to becoming one of the world's biggest corporations, is expected to buy the company. Dre was already a successful hip-hop performer and producer, but his name alone would not have been enough to transform colorful, outsize headphones into fashion accessories. Next was an aggressive marketing push that saw the iconic red "b" logo appearing at sporting events and around the necks of superstar singers and club DJs. When bad boy footballers like Wayne Rooney or Mario Balotelli descend from a team bus outside a stadium on a match night, they are inevitably shielded by a pair. Rival manufacturer Panasonic sponsored the 2012 London Olympics and tried to keep the Beats logo off camera. But the upstart Californian firm had sent dozens of sets of its headphones as gifts to leading sports stars, and they inevitably turned up in much of the coverage of the event. And while sports stars may be using Beats to retreat from the world in preparation for an event, musicians like Lady Gaga and Eminem have incorporated them in their flamboyant appearances. The brand crossed genres from hip-hop to electronic dance music when it collaborated with French DJ David Guetta to develop a version suited for use with his turntables. - Marketing genius - It has all apparently paid off. Neither Apple nor Beats have confirmed the reported buy-out, but Dre was seen in a YouTube video Friday boasting of being the "first billionaire in hip-hop." A few weeks earlier, in an interview with US sports network ESPN, the basketball fan Dre had spoken of more modest ambitions. "We were just trying to uplift sound and change the way people listen to music. Our thing was to make music sound the way we hear it in the studio," he declared. "We had no idea this was going to happen," he said. "That's crazy, it means that Beats has gone from zero to full-blown cultural phenomenon in less than five years."