Microsoft has confirmed that it has agreed to buy internet phone service Skype.
The deal will see Microsoft pay $8.5bn (£5.2bn) for Skype, making it Microsoft's largest acquisition.
Luxembourg-based Skype has 663 million global users. In August last year it announced plans for a share flotation, but this was subsequently put on hold.
Internet auction house eBay bought Skype for $2.6bn in 2006, before selling 70% of it in 2009 for $2bn.
This majority stake was bought by a group of investors led by private equity firms Silver Lake and Andreessen Horowit.
Other major shareholders include tech-firm Joltid and the Canada Pension Plan Investment Board.
'Defensive move'
Microsoft chief executive Steve Ballmer said: "Skype is a phenomenal service that is loved by millions of people around the world.