MONDAY, OCTOBER 20

"GOSSIP GIRL" � (8:00-9:00 p.m. ET)

"Chuck In Real Life" (CONTENT RATING TBD) (HDTV)

BLAIR CONVINCES CHUCK TO SEDUCE VANESSA � Vanessa (Jessica Szohr) uses the scandalous picture of Catherine and Marcus to blackmail Blair (Leighton Meester) into being a nicer person, so Blair seeks revenge by enticing Chuck (Ed Westwick) to seduce Vanessa. Lily (Kelly Rutherford) and Bart (guest star Robert John Burke) throw an extravagant housewarming party and expect their children to make them proud in front of the attending press, but a rebellious Serena (Blake Lively) isn't ready to play by their rules. Meanwhile, Dan (Penn Badgley) and Jenny (Taylor Momsen) discover a big secret that Nate (Chace Crawford) has been keeping from his friends. Matthew Settle also stars. Tony Wharmby directed the episode written by Lenn K. Rosenfeld (#207).