The pole dancer allegedly attended raunchy parties thrown by the 76-year-old former premier minister in his private residence in Milan in 2010, where she has claimed he showered her with money and gifts, when she was just 17.
As Italian magistrates launched a probe into the premier's private life in 2011, Ruby became the pin-up girl for the Italian media's sensational coverage of rumoured orgies hosted by Berlusconi, with prostitutes and showgirls.
Ruby – whose real name is Karima El Mahroug – was born on November 1st, 1992, and moved with her family from Morocco to a small town in Sicily in 2003.
She lived with her hawker father, housewife mother and three younger siblings before running away from home at 14.
Spotted by one of Berlusconi's cronies at a beauty contest in Sicily, Ruby was called to entertain the then prime minister by Nicole Minetti, a trusted aide and regional representative for his party who is now on trial on pimping charges.
It was Minetti who then helped get Ruby out of prison after she was arrested for alleged theft in May 2010, when she was accused of stealing a bracelet worth 3,000 euros ($3,941).
Berlusconi rang the police station and told officials to release her, claiming she was the niece of then Egyptian president Hosni Mubarak and asking police to hand her over to Minetti, ostensibly to prevent diplomatic fallout.
The indignant three-time premier later protested he had no idea that Ruby was not Mubarak's niece, claiming the story was part of a series of lies that the teenager had told him, including fibbing about her age.
The dark-haired, long-lashed girl became the star of the scandal, pouting in paparazzi photographs and later appearing on several television channels protesting her innocence and telling the harrowing story of her troubled past.
Grilled by investigators, she said she met Berlusconi at one of his "bunga-bunga" parties – where she described naked women who surround the aged premier, vying with each other to arouse him – but denied taking part.
She later changed her story, however, telling a court this year that she had previously lied about the raunchy parties, insisting "the majority of the things I said were not true" – including how much money he gave her.
She also admitted lying about having sex for money with Portuguese footballer Cristiano Ronaldo, saying she had got the idea from a billboard picture of him in his underwear.
"If I didn't prostitute myself with Ronaldo, who is good-looking, you can forget about Berlusconi," she said.
In a protest staged outside a Milan court house in April, she claimed she was the victim of "psychological warfare".
"The only 'proof' provided in the trial that I was prostituting myself were some photographs that the head of the investigators showed in court, after having downloaded them from my Facebook profile. A ridiculous thing," she said.
"At the time I was just 17 and I did not take into account what prosecutors and the press might make of them," she added.
While initially hogging the limelight with her revealing dresses and push-up bras, the young Moroccan has always spoken affectionately of Berlusconi, whom she has described as a charitable but lonely man, forced to buy women's affection.
After confessing to journalists she wanted to change her ways, Ruby married a 43-year-old nightclub manager with whom she had a baby girl, and largely disappeared from public view.