The 56-year-old actor co-founded the tequila company, Casamigos (meaning "house of friends"), with a group of friends four years ago, citing their love for the drink as their main reason for setting up the business.

Now, their investment has paid off big time, with the company being bought outright by Diageo, the world's second largest distiller, whose brands also include Smirnoff, Bailey's, Johnnie Walker and Guinness.

In a statement about the sale, Clooney said: "If you asked us four years ago if we had a billion-dollar company, I don’t think we would have said yes."

The Hollywood actor isn't the only moviestar to self-make their own business empire. Mark and Donnie Wahlberg set up the brilliantly titled "Wahlburger" fast food chain in 2011 (which now has its own reality TV series), Drake has his own whiskey company (Virginia Black Whiskey), and Bono himself made a clean $1.4billion when his investment group Elevation Partners bought a share in Facebook back in 2009.