The acquisition pre-empted a supposed auction of the brands which had attracted interest from private equity firms such as Blackstone, Lion Capital, Cinven, CVC Capital Partners and KKR while trade players such as Irn-Bru maker AG Barr were also thought to be interested.
However, Suntory, which owns Scotch whisky firm Morrison Bowmore, appeared to be in pole position after it emerged talks between it and GSK had reached an advanced stage.
Yesterday, it was confirmed Suntory had won the race.
The latest transaction builds on its 2009 takeover of Orangina Schweppes for £2.2bn which gave it operations in France and Spain.
It also allows the company to get into countries such as Nigeria and Malaysia where GSK already operates.
Around 700 staff, mainly based at a factory at Coleford, Gloucestershire, are expected to transfer across to the new Japanese owners.
GSK, which is offloading the brands to concentrate on its consumer health business, said the deal should complete before the end of this year if regulatory approval is received.
After the deduction of costs, GSK should net around £1.3bn some of which will be used to reduce debt.
Suntory, best known for its Japanese whisky, said the deal would have a limited effect on 2013 results and it was examining the prospects for 2014 and onwards.