Ms Letizia sports the gold and diamond pendant given to her by the PM
Italian Prime Minister Silvio Berlusconi has denied lying about his relationship with a young single woman who is at the centre of a marital row.
"There was nothing negative" about his friendship with Noemi Letizia, Mr Berlusconi told US TV channel CNN.
He said he planned to appear before parliament soon to clarify his actions.
Mr Berlusconi's wife, Veronica Lario, said she would divorce him after it was reported he attended Ms Letizia's 18th birthday party in Naples.
Mr Berlusconi was reported to have bought her a gold necklace studded with diamonds as a present.
BEING MRS BERLUSCONI
In Feb 2007, Veronica demanded a public apology from her husband for his flirting, to which he replied with a written one
In the 2004 biography Veronica's Tendency she revealed that "Silvio eats lunch while attached to the phone and dinner is the same"
Veronica rarely accompanies her husband on foreign trips
The couple met in 1980, wed 10 years later and have three children in their 20s
Mr Berlusconi has said he was smitten when he first saw the 24-year-old actress on stage
At the time the Italian prime minister said he only went to the party because he happened to be in the city that day and was an old friend of the aspiring model's father.
"It is disgraceful the conduct of people who invade privacy and use private matters for political attacks," he told CNN, referring to opposition calls for an explanation.
The BBC's Duncan Kennedy in Rome says the controversy is not a full-blown personal or political scandal yet, but the prime minister needs to act to stop it becoming one.
For Ms Lario revelations that her 72-year-old husband attended the birthday party of the young woman - who calls him Papi - prompted her to let it be known that she wanted a divorce.
"I cannot remain with a man who consorts with minors," Ms Lario was quoted as saying in the left-of-centre newspaper La Repubblica.
Relations with her husband were already said to be frayed after Ms Lario had criticised his choice of young and attractive female candidates with little political experience to represent his Freedom Party in the forthcoming European elections.