Bono is reportedly the world's richest pop star after his investment in Facebook shares earned him $1.5 billion.

The U2 frontman bought a 2.3 per cent share in Mark Zuckerberg's social media network in 2009 for $86 million with Elevation Partners, an investment group he co-founded.

Now that share is said to be worth $1.5 billion, according to reports.

This means that the singer and philanthropist's social media venture has earned him more in the last six years than the whole of his music career.

This investment has seen Bono take over from Beatles star Paul McCartney as the world's richest pop star, with Madonna taking third position in the list.