MONDAY, DECEMBER 15

"GOSSIP GIRL" � (8:00-9:00 p.m. ET)

"The Serena Also Rises" (CONTENT RATING TBD) (HDTV)

FASHION WEEK DRAMA! / DESIGNER MICHAEL KORS AND SOCIALITES TINSLEY MORTIMER AND CRISTINA CUOMO MAKE CAMEO APPEARANCES AT ELEANOR WALDORF'S SHOW � In the midst of Fashion Week, a furious Blair (Leighton Meester) learns that her mother, Eleanor (guest star Margaret Colin), at the suggestion of her prot�g� Jenny (Taylor Momsen), has given Serena (Blake Lively) and her new socialite friend, Poppy Lifton (guest star Tamara Feldman), front row seats to the Eleanor Waldorf show. Hurt once again by Serena's popularity and her mother's betrayal, Blair decides to sabotage the show. Meanwhile, Dan (Penn Badgley) starts hanging out with Chuck (Ed Westwick), but a walk on the dark side always has its risks and Dan learns that the hard way. Lily (Kelly Rutherford) learns a secret that her new husband, Bart (guest start Robert John Burke), has been keeping from her. Matthew Settle also stars. Patrick Norris directed the episode written by Jessica Queller (#205).