Yes, and that is not really a great surprise, but certainly a great news, Metal Gear Rising was released to PC early of this year and it have ports of Metal Gear Solid and Metal Gear Solid 2 and now Metal Gear Solid Ground Zeroes and Phantom Pain wll come to Steam, looks like Konami accidentally leaked today just before a big MGS livestream.
And bellow you an watch the official announcement of MGV for Steam;