FIRST OFF . . .

Actor Sean Penn faces possible charges in the wake of his arrest for driving while under the influence of alcohol, police said. Penn, 26, was stopped by a Wilshire Division patrol unit Monday night because he allegedly was traveling too fast and ran a red light, Los Angeles Police Department spokesman Lt. Dan Cooke said. The co-star of “Falcon and the Snowman” and “At Close Range” failed field sobriety and “breathalizer” tests, Cooke said. Penn was described as cooperative during the arrest, and was booked at the Wilshire jail before being released on his own recognizance. Ironically, Penn just completed “Colors,” in which he plays a Los Angeles Police Department anti-gang unit detective.

Also on the LAPD celebrity blotter: TV’s “Moonlighting” wise guy Bruce Willis was arrested--sans shirt--on Monday night for allegedly assaulting an officer as police broke up a raucous party at his Nichols Canyon home, LAPD authorities said Monday. LAPD Sgt. Joe Bustos said Willis, 32, and another man were arrested on a misdemeanor battery charge because they pushed an officer. Three partygoers also were arrested for interfering with police after Willis was arrested. Officers were called to Willis’ home about 11:30 p.m. Monday after a number of the actor’s neighbors called to complain about loud music during a party there, Bustos said. “It’s not the first time (the neighbors complained),” added LAPD Sgt. Mike Schneider. “So the officers went up there and (Willis) charged one of the officers and he was handcuffed.” It was also reported Tuesday that during the scuffle, Willis reinjured the collarbone he hurt in a skiing accident earlier this year and was taken to a hospital before being booked.