Facebook co-founder and head engineer Dustin Moskovitz is to leave the social networking site to start his own internet service.
Moskovitz, who launched the social networking site with while at Harvard with company chief executive Mark Zuckerberg, is understood to be leaving in a month to form a start-up with Facebook manager Justin Rosenstein that will look to build software products for users of the social network.
In a short statement the company confirmed Moskovitz's departure.
"Dustin has always had Facebook's best interest at heart and will always be someone I turn to for advice," Zuckerberg said in the statement released on Friday.
Moskovitz is the latest executive to leave company based in Palo Alto, California, as goes through an expansion phase.
Former Google executive Sheryl Sandberg recently joined the company as chief operating officer.
The company also announced at the end of last week plans to open an international headquarters in Dublin, Ireland.
Following its creation in 2004 by Zuckerberg, Moskovitz and Chris Hughes, Facebook quickly became an internet, business and social phenomenon with more than 100 million users worldwide.
Despite being offered billions for the site, Zuckerberg has remained independent, taking investment from just a few interested parties, including PayPal creator Peter Thiel and Microsoft.
The company was reportedly valued at about £8bn last year when Microsoft invested approximately £125m for a small stake in the company.
Facebook's key rivals in social networking, MySpace and Bebo, have both sold out to larger media organisations.
MySpace was bought by Rupert Murdoch's News Corporation for $580m (£299m) in 2005, while Bebo was sold to Time Warner's internet arm, AOL, in March this year for $850m.
