Blair Waldorf and Serena van der Woodsen live at 1136 Fifth Avenue, New York NY 10128 in the penthouse. Lily van der Woodsen and her family lived in suites at 455 Madison Avenue, New York, NY 10022 - otherwise known as the Palace Hotel until moving to the Milan Condominium at 300 East 55th Street, New York, NY.
William Baldwin, who played Serena van der Woodsen's absentee father, avoided meeting his onscreen daughter Blake Lively until the cameras rolled so that they could have a more realistic, strained relationship.
Kristen Bell, the infamous voice of Gossip Girl over the show's entire 6-season run, gushed that she wished she had gotten to play "some vicious part and actually come out as Gossip Girl" in the final season of the series.
The name of Rufus' band, "Lincoln Hawk", is also the name of Sylvester Stallone's character in the movie Over the Top (1987). That movie is mentioned several times as being a cult-classic in The O.C. (2003), the previous show from Josh Schwartz, the creator of this series.
Was originally pitched as a feature with Lindsay Lohan as Blair Waldorf. When that fell through, its backers (who had the rights to the stories) approached Josh Schwartz about turning it into a series.
The show's beginning date took place, chronologically, after it was aired. The show aired in Canada on September 18, 2007 and aired in the US on September 19, 2007. The show starts on Wednesday September 23, 2007 and ends on Saturday September 26, 2007, thus all dates in the Pilot fall after their air date.