Contrary to popular belief, Chuck's Uncle Jack (guest star Desmond Harrington) is very much alive and most probably scheming something down under. According to TV Guide, Uncle Jack will be back on a future episode, and Blair (Leighton Meester) is not exactly thrilled about it. If a preview is to be believed, Chuck (Ed Westwick) already knows that Blair and Uncle Jack did something on New Year's Day, and it wasn't just dinner and champagne.
A controversial exchange on one of the first episodes of the year had Blair and Jack talking about Blair not trusting him and Jack telling her that she had no choice. She then dropped the bomb, He can't know about New Year's. with he obviously referring to Chuck.