Earlier today, it was announced that Baldwin brother Billy will take on the role of Serena van der Woodsen's estranged father in an upcoming episode of Gossip Girl. Long known as the most attractive and, arguably, the second-most successful Baldwin, he does bear a more than a passing resemblance to actress and future TV daughter Blake Lively. His arrival is sure to upset the already-troubled-enough Serena, not to mention relations between her mother Lily (Kelly Rutherford) and her latest husband, Rufus (Matthew Settle). How, exactly? There's no way to know until March 8, when the series returns, but feel free to venture a guess based on our brief survey (above) of Billy's family ties, both on and off screen.