It's a theory that has been around for almost a century: There are no more than six degrees of separation between any two people on the planet.

But according to a study from Facebook, the world is actually smaller than we think. The social network has found there are on average just three and a half people between any one person and another.

Facebook analysed the hundreds of billions of connections between its users to determine a new figure for the six degrees of separation theory, which was coined by the Hungarian playwright Frigyes Karinthy in 1929 and has been extensively studied.

While Karinthy speculated that a chain of just six individuals between people can link any two on the planet, Facebook's study suggests there are in fact just 3.57 intermediaries, or degrees of separation.