LOS ANGELES – Hunger drove Paris Hilton to drink and drive, her rep says.

The willowy starlet, busted and handcuffed early yesterday on a drunken driving charge in Hollywood, was famished from a long day of working and schmoozing without eating when she headed out for a burger after downing “one margarita” at a charity bash, her spokesman Elliott Mintz told the Daily News.

“She had not eaten all day. She was a little weak. She left the event intending to go to In-N-Out Burger,” Mintz said. “She is a big fan of fast food.”

“She regrets what happened. She did not take this matter lightly or frivolously. She had never been arrested before, and it was clearly humiliating and disorienting,” Mintz said.

The 25-year-old, pencil-thin party girl blew 0.08 on the alcohol breath test – the minimum level at which a driver can be charged in California – after motorcycle cops pulled her over for “driving erratically” at 12:31 a.m. in central Hollywood, police said.

After failing a field sobriety test, the hotel heiress was slapped in handcuffs and booked at the Hollywood Division station, said an LAPD spokeswoman, Officer Martha Garcia. Hilton spent “a couple of hours” in lockup before she was released on her own recognizance around 3 a.m., Garcia said.

Hilton’s passenger at the time of her arrest, rocker Rod Stewart’s daughter Kimberly, “also appeared to be intoxicated, so the Mercedes was impounded,” Garcia said.

Paris’ frantic sister Nicky Hilton, clad in short black shorts and a black baby-doll top, and Nicky’s boyfriend, “Entourage” star Kevin Connolly, showed up at the station around 2 a.m. to await her release.

Mintz said Paris Hilton wasn’t wasting away in margaritaville when she climbed behind the wheel after attending a Head To Hollywood charity bash hosted by Carmen Electra. Hilton drank one margarita on an empty stomach, Mintz said.

Paris’ claim of reaching .08 after having just one margarita is consistent with the California DMV’s Alcohol Impairment Chart, which says that a person weighing 90 to 129 pounds who consumes one, 11/4-ounce shot of 80 proof alcohol in one hour will have a blood alcohol level of up to .07. Because the average margarita has about 2 ounces of alcohol, a .08 reading could result from drinking just one.

“Paris regrets getting behind the wheel with even one drink,” said Mintz.