By Nicholas Fonseca
Updated July 27, 2001 at 04:00 AM EDT

EXPECTING Actress Laura Dern (Jurassic Park III), 34, and folk-rock hipster Ben Harper, 31, are expecting a baby this fall. They’ve been dating for six months. This will be Dern’s first child; Harper has two kids from a previous marriage.

ENGAGED No joke: Late-night funny guy Conan O’Brien, 38, has agreed to wed ad-agency creative director Liza Powell, 30. This will be the first marriage for both.

COUPLES Isn’t this how he met Nicole? Reports that newly available superstar Tom Cruise, 39, has eyes for his Vanilla Sky costar Penelope Cruz, 27, have been confirmed by his spokeswoman, who told the press that the pair recently went on ”a few dates.”

SPLITS How will she live without him? A spokeswoman for LeAnn Rimes, 18, confirms that the temperamental country-pop princess has broken off with her boyfriend of three years, actor Andrew Keegan (The Broken Hearts Club), 22.

DEALS Baked ziti all around! The Sopranos creator David Chase, 55, reportedly has agreed to helm a fifth season of his HBO hit for an estimated $20 million. An HBO rep says the cable net hasn’t officially committed to another season after the fourth one airs next year.

COURTS Bad-boy rapper Eminem’s famously estranged wife, Kimberly Mathers, 26, turned herself in July 16 in Mount Clemens, Mich., to face a felony charge of cocaine possession. A suspect baggie was found under the seat of a patrol car in which she’d been riding after her July 8 arrest for a previous disorderly-conduct charge. If convicted of the coke charge, Mathers could face up to four years in prison. (She’s scheduled to appear in court next month to answer the disturbance charge.) Says her lawyer, ”We’re confident we’ll be able to show [the cocaine] was not hers.”… After pleading no contest July 16 to drug charges (one felony and one misdemeanor), Robert Downey Jr., 36, was sentenced to three years’ probation and ordered to remain in rehab for at least a year. The actor was arrested last November at a Palm Springs, Calif., resort. L.A. prosecutors decided not to file charges against Downey after he was arrested for an alleged similar offense in April….Now Reege is in the hot seat. On July 10, former Who Wants to Be a Millionaire contestant Richard Rosner, 41, filed suit against ABC and Valleycrest Productions, claiming he was unfairly eliminated at the $16,000 mark last July. The question: ”What capital city is located at the highest altitude above sea level?” Rosner claims the world’s highest capital was not among the choices provided. He seeks another shot on the show, or at least $1 million in damages. ABC and Valleycrest had no comment….On July 13 in Philadelphia, rapper Beanie Sigel (a.k.a. Dwight Grant), 27, was charged with four assault-related counts (including two felonies) after he allegedly beat a motorist on Sigel Street — from which he borrowed his stage name. Sigel could face up to 44 years in jail. Police refused to name the alleged victim. Sigel’s spokeswoman did not return calls…. Gravel-voiced rapper DMX (a.k.a. Earl Simmons), 30, was indicted June 20 on a mis-demeanor criminal-contempt charge in Buffalo, stemming from his failure to appear on time in February to begin serving a sentence for a previous conviction for driving without a license. (He has since served the 15-day term.) DMX could face up to a year in jail on the contempt charge. His rep had no comment.