Dressed in a transparent leopard-print top and velvet boots, Karima El Mahroug, 18, settled into an armchair and stared into the TV camera last night, ready to face the Italian public.

With her long chestnut locks teased carefully around her shoulders, the belly dancer, who allegedly traded sexual favors for money and jewels from Italian Prime Minister Silvio Berlusconi, suddenly broke down.

The 74-year-old leader, she said, did “not even lay a finger on me.”

READ MORE: SEX ON TAPE: THE WIRETAPS

But El Mahroug — famously dubbed “Ruby Heartstealer” — was not an entirely convincing interviewee. That’s because what Ruby says in public is quite different from what she’s been recorded saying in private.

Over the past few months, Italian investigators have been wiretapping Ruby and other partygoers as part of a probe into Berlusconi for corruption and having sex with underage prostitutes.

For years, Berlusconi is said to have showered money, jewels and cars on “significant numbers” of women in return for sexual favors at Bacchanalian parties at his villa in Arcore, near Milan; his residence in Rome and his holiday home in Sardinia. He has always denied the allegations.

But now that wiretaps revealing the sordid details were released to the Italian media on Tuesday, Berlusconi is facing fresh humiliation and calls to resign.

Within the 390-page dossier is a statement from Ruby’s former roommate, Caterina Pasquina, who told prosecutors: “[El Mahroug] said she was very friendly with the prime minister, Silvio Berlusconi. She often went to his house for dinner, and she had sex with him, for which he gave her lots of money.” Meanwhile, in another wiretap, Ruby tells a friend: “I’ve been going to the prime minister’s house since I was 16 years old, but I have always denied everything to protect him.”

According to the tapes, women dressed up in police and nurse uniforms to perform stripteases for Berlusconi and two of his cronies.

One transcript included a conversation between a former chief of police intelligence, Carlo Ferrigno, and a friend who said of the parties: “There were orgies in there . . . they were all drinking, half undressed.

“Three [men] and 28 girls. By the end . . . the girls had no bras on and were wearing only those tight knickers.”

Moroccan-born “Ruby” was just 17 at the time, and therefore was still a minor when she attended her first party at Berlusconi’s villa at Arcore last year.

In Italy, the age of consent for sex is 14, but paying someone under the age of 18 for sex is an offense punishable by up to three years in jail.

Prosecutors took an active interest in Ruby when they discovered Berlusconi had telephoned a Milan police station last May after she was arrested for stealing 3,000 euros, or a little more than $4,000, from a friend.

Berlusconi is said to have wrongly told the custody officer that she was the granddaughter of Egyptian President Hosni Mubarak, and that she should be released to prevent a diplomatic incident. She duly was.

Ruby, who is living in Italy illegally, had run away to Milan from her home in Sicily when she was 16, and is said to have met Berlusconi after appearing at lap-dancing clubs.

When her name first emerged in the scandal, she said Berlusconi had given her money, jewels and a car, but that they had “never had sex.” Soon after, Ruby became famous — going on a whirl of nightclub appearances (for which she received $2,000 a pop), traveling by chauffeur-driven Ferraris, sitting on a throne and posing for pictures while sipping Champagne.

All the while, prosecutors carried on investigating the Milan police-station incident, also tapping calls between the dancer and several of her friends, as well as with

several guests at the parties.

They slowly began to build their case, and last month, in secret, officially told Berlusconi that he was under investigation for extortion (of the custody officer) and underage prostitution.

According to wiretaps, one partygoer said that twins Imma and Eleonora De Vivo, 30, who appeared on the Italian version of “I’m a Celebrity . . . Get Me Out of Here,” were paid to have sex with Berlusconi.

Other TV stars were also regulars at the parties, and it was claimed that some women put on a “lesbian-style” show for him and his cronies. Regional politician Nicole Minetti, 25, a former dental hygienist, was said to have recruited the girls.

According to a wiretap transcript, a former police officer is heard saying: “Minetti was there, kissing Berlusconi . . . the girls were given rings and necklaces.”

In another conversation, one woman tells another: “You either do everything or you take a taxi and leave. It’s a real whorehouse there. Berlusconi is touching all the girls’ bottoms. It’s worse than the papers say.”

With the details dominating Italian newspapers and TV, even the Catholic Church weighed in, saying it was “wounded and shocked” by the tawdry revelations.

Last weekend, after it emerged that Berlusconi was under investigation, he made a 15-minute prime-time TV appearance and said: “These allegations cannot possibly be true as, since separating from my wife, I have been in a stable relationship with another woman who would not have approved of such parties.”

His confession prompted a guessing game in the Italian media as to the identity of the lucky lady.

The favorite is Roberta Bonasia, 26, a former nurse turned beauty queen. She insisted she had never been to Berlusconi’s house, and that she didn’t know him.

Like the others, however, she was betrayed by a phone call: “[Berlusconi] has asked me to get some girls together,” she told her brother in a wiretapped conversation.

While Ruby remains loyal to the prime minister, her private comments could lead to his undoing.

“[Berlusconi] called me and said, ‘Ruby, I’ll give you whatever amount you want,’ ” one of the wiretaps reveals her as saying. “ ‘I’ll pay you. I’ll cover you in gold, but the important thing is to keep everything under wraps. Don’t say a thing to anyone.’”

After this week’s revelations, it appears that silence is no longer so easily bought.