There are plenty of obvious things that all celebrities seem to have in common. Namely an enviable closet, a substantial pay cheque, and — for several ladies on the list — a shared spotlight with Matthew McConaughey. But, it's actually a subtle detail that ties them all together — one that's as ubiquitous on the red carpet as Giuliana Rancic. We are of course referring to the bright red sole of a Christian Louboutin heel. It's the signature flash of colour that lets you and everyone standing behind you know that your shoes are not only luxe, but made by someone who's as obsessed with sexy footwear as it gets. And, someone who's celebrating a birthday today.