Fox will use three Thursday nights of the all-important May sweeps month to promote Fox pictures’ May 16 release of “Star Wars: Episode II Attack of the Clones.” During the next three weeks, Fox will broadcast the second, third and fourth “Star Wars” movies, beginning tonight with the 1980 hit “The Empire Strikes Back” (7 p.m.). Each film will be introduced by the robot tag team of C-3PO and R2-D2 and include never-before-seen footage. Rest assured, Fox will air plenty of clips from the forthcoming “Clones.”

Put two “Star Wars” aficionados in a room and you will probably get three opinions, but many fans agree that “The Empire Strikes Back” is the best of the movies to date. “Empire” introduced audiences to the cryptic Jedi Master Yoda and expanded on the complicated connection and rivalry between Darth Vader (James Earl Jones) and Luke Skywalker (Mark Hamill). “Simpsons” fans may recall that Homer and Marge went to see “The Empire Strikes Back” in the flashback episode in which Homer proposes to his blue-haired beloved. “You have the wisdom of Yoda,” he gushes, “and the beauty of Princess Leia.” D’Oh!

Fox will broadcast “Return of the Jedi” on May 2 and “Phantom Menace” on May 9. Fox affiliates will pre-empt their local news to air these three-hour films in their entirety.

Years before he became a box-office draw with such films as “Romancing the Stone,” and “Fatal Attraction,” Michael Douglas was the young Inspector Steve Keller on the 1970s cop drama “Streets of San Francisco.” Douglas draws on his TV cop experience as well as his “Basic Instinct” performance as a kinky and mentally unbalanced detective to turn in an unforgettable performance on “Will & Grace” (8 p.m., NBC).

Douglas plays a gay New York detective with a crush on Will and a peculiar aversion to people with food caught in their teeth. A manic subplot reunites Grace with her deranged neighbor Val (Molly Shannon) who takes her penchant for petty theft to a whole new level. Star-studded sweeps events are often more about hype than comedy. This episode is witty, weird and wonderful from start to finish.

Tonight’s other highlights

On back-to-back episodes of “Friends” (NBC) Ross freaks out when Rachel’s mother (Marlo Thomas) moves in to help her prepare for the baby (7 p.m.), Rachel guards the secret of her baby’s paternity (8 p.m.).

“The Bachelor” (7 p.m., ABC) makes his big decision on two consecutive episodes. The 8 p.m. episode is the season finale.

The boy band performs their hits on “N’SYNC: Bigger Than Live” (7 p.m., WB).

A woman’s body is found, partially devoured by her many cats, on “CSI” (8 p.m., CBS). Beginning Sept. 9, fans of this crime drama can catch repeats in syndication on TNN.

“Frontline” (9 p.m., PBS) re-examines the hysterical atmosphere surrounding a child molestation case that earned a Florida man a life sentence.

Working undercover as an arms dealer, Jackson falls into the hands of Russian mobsters on “The Agency” (9 p.m., CBS).

A troubling call from her niece sends Lewis to New York to search for her sister on “ER” (9 p.m., NBC). The first of a two-part crossover episode with “Third Watch.”

Scheduled on “Primetime” (9 p.m., ABC): a hidden-camera look at the children of angry, feuding parents.

Series notes

Eight remaining contestants compete on “Survivor: Marquesas” (7 p.m., CBS) Wrestling on “WWF Smackdown” (7 p.m., UPN) . Phoebe opts for evil on “Charmed” (8 p.m., WB) Elliott resents his grandmother’s desire to spend time with Finch on “Just Shoot Me” (8:30 p.m., NBC).

Late night

All are new Jessica Alba and Ceelo appear on “Late Show with David Letterman” (10:35 p.m., CBS) Jay Leno hosts Jennifer Love Hewitt and Eugene Levy on “The Tonight Show” (10:35 p.m., NBC).

Bill Maher welcomes Ralph Nader, Fran Drescher and Doug McIntyre on “Politically Incorrect” (11:05 p.m., ABC).

Ted Danson chats on “Late Night with Conan O’Brien” (11:35 p.m., NBC) The Rock and Mila Kunis are booked on “The Late, Late Show with Craig Kilborn” (11:37 p.m., CBS).