superficial appeal. Sports stars arguably make natural underwear manufacturers because they understand more than most about the importance of comfort on the go. If you have the right underwear you feel more confidence on the court or off the court, explains Nyvang. It's important for sporting performance. At Bjorn Borg we focus on the perfect fit and we are also very fashion conscious. We put out underwear that makes people feel more active and attractive. But before you dream about wrapping up a Nigel de Jong thong or a pair of Neymar knickers for your loved ones, bear in mind it takes a certain type of star to make money from undies. You are talking about one-offs here, says Martin. There are probably only a handful of global sports stars that can attempt something like this. For every Ronaldo there are thousands and thousands and thousands of footballers who do n't make a thousandth of what he does. Stevenson agrees that true sporting icons stand a better chance of successfully creating a product line that is not directly connected to their core business -- but that even then there could be pit falls.