Let me know if you've discovered any others! ;p

.....
Gossip Girl Actors/Actresses B-DAYS!!! (and their teen characters. ;p)
1.
Ed Westwick—June 27, 1987
(Chuck Bass)—May 19, 1991

2.
Leighton Meester—April 9, 1986
(Blair Waldorf)—November 17, 1990

3.
Chase Crawford—July 18, 1985
(Nathaniel Archibald)--???

4.
Blake Lively—August 25, 1987
(Serena van der Woodsen—July 14

5.
Penn Badgley—November 1, 1986
(Dan Humphrey)--???

6.
Jessica Szohr—March 31, 1985
(Vanessa Abrams)--???

7.
Taylor Momsen—July 26, 1993
(Jennifer/Jenny Humphrey)--???