MONDAY, APRIL 26

"GOSSIP GIRL" - (9:00-10:00 p.m. ET)

"Dr. Estrangeloved" (TV-14, D) (HDTV)

WILLIAM "BILLY" BALDWIN ("DIRTY SEXY MONEY") GUEST STARS - When Lily's (Kelly Rutherford) ex-husband, Dr. William van der Woodsen (Baldwin), shows up unexpectedly in Manhattan, Serena (Blake Lively) finally gets the reunion she has so desperately wanted with her father, but the circumstances turn out to be far from ideal. When Serena and Nate (Chace Crawford) continue to have relationship issues, a scheming Jenny (Taylor Momsen) is more than happy to be a shoulder for Nate to lean on. Meanwhile, Dan (Penn Badgley) finds out that he didn't get accepted into the Tisch writing program and Vanessa (Jessica Szohr) admits she may have been somewhat responsible. Leighton Meester, Ed Westwick and Matthew Settle also star. Darnell Martin directed the episode written by Robert Hull (#319).