Want to know what sunglasses Tom Cruise and Katie Holmes were wearing in Madrid last Sunday? There are dozens of websites to tell you.

Chances are that many of the celebrities’ favourite brands are owned by Luxottica, the Italian eyewear group. It is now adding another name, Oakley, the California-based sunglasses maker, to a portfolio that already includes Prada and Chanel. And it is paying a rather fashionable price to do so.