Is Mark Zuckerberg engaged? Bill Gates lets slip that his billionaire pal may be about to update his Facebook status

For women around the world, billionaire Facebook founder Mark Zuckerberg would be the ultimate catch.
But if Microsoft founder Bill Gates is to be believed he's already taken -- engaged to long-time girlfriend Priscilla Chan.Has Mr Gates just revealed the cyberworld's best-kept secret, or did he just use the wrong word when described Miss Chan as Mr Zuckerberg's 'fiancee'?Mr Gates is friends with Mr Zuckerberg, 26, who has pledged to give most of his fortune away.

Earlier this year they adopted a puppy named Beast and looked every bit the happy young family when they posed for photos with the dog.But the mystery deepens when you look at their respective profile pages.The social network king made headlines when he dropped $7 million on a 5,000 square feet palace in Palo Alto, California, and last month the couple moved in.It could have been a slip of the tongue, saying fiancee instead of girlfriend, but the news would certainly add up. Mr Zuckerberg has been dating Miss Chan since 2003. 'His fiancée Priscilla thought about education and he gave money to Newark, New Jersey, and we did a co-grant so that some of our people who had some expertise in that field could help him out.'In an exclusive interview with the Mail on Sunday, when discussing their philanthropic efforts, Mr Gates said: ‘I didn't say to Mark, "Give me all your money!" He was predisposed to do it and he came to me seeking advice.