When professional party girls Paris Hilton and Tara Reid hit Miami for the weekend, it turned into a crazy club crawl full of vodka, vomiting, melted wax and O.J. Simpson!

Hilton, Reid and a posse of hangers-on, in town for the Grand Prix Americas race, were first spotted at Elton John’s concert at the American Airlines Arena September 27.

But rather than rock out to “Rocket Man,” Hilton, 22, left her second-row seat for a handicapped stall in the ladies’ room, where she tried to book a flight from Miami to Chicago.

“What’s the earliest I can get tomorrow?” a Manolo Blahnik-sporting, see-through-blue-dress-wearing Hilton asked on her cell phone.

“Coach is fine. Yes. O.K. Um. Well, I’m a supermodel.”

While Hilton, who stars in the upcoming FOX reality show “The Simple Life,” was booking her flight, Reid, in a barely there black miniskirt and halter top, was at the arena’s bar surrounded by male admirers.

“I didn’t come to Miami to attend a concert,” the “American Pie” star complained. “I want to party. Where is my drink?”

After downing two vodka and cranberry drinks, Reid, 27, made her way back to her seat at the concert — not far from “American Idol” host Ryan Seacrest — to wait for Hilton.

“Paris would never leave,” she declared. “She is like my little sister. She does everything I tell her to do.”

When the concert ended, the blonde booze buddies went to Metro Kitchen and Bar, where an uninvited O.J. Simpson was taking in the scene.

“I’d love to get a piece of that,” Simpson muttered, referring to Hilton. At which point, Hilton turned to Reid and said, “Ugh, look who’s here, I am nauseous.”

After smiling for dozens of photos, Hilton was asked to pose with Simpson. She responded, “Are you kidding? No way. Ever. Eww.”

Then the party girls headed for the official after-bash at the nightclub Opium Garden, where half-naked S&M girls were up on the bar dripping hot wax on each other.

“Ugh, those women are gross,” Hilton snapped before storming out.

Meanwhile, Reid was out front throwing up.

“She totally lost her cookies,” said an eyewitness. “She was wasted.”

But Reid had only just begun to party. She and Hilton next went off to the after-hours dance club, Space34.

“They were so whacked-out,” said an eyewitness.

The next day, a visibly hungover Reid showed up at the race, minus Hilton.

“That girl looks like she was out all night,” said one bystander.

“She was,” replied an eyewitness to the carousing. “And it wasn’t pretty.”