PARIS (AFP) - French actress Julie Gayet has remained "very calm" since allegations she was having an affair with President Francois Hollande were made public, her former husband said on Monday.

"It's obviously not easy. At the same time, she's very calm about it all and very sure of herself, I think, because there was no fault, no betrayal," said the Argentinian writer Santiago Amigorena on Europe 1 radio.

"I am not her spokesman, in any case I think I know her very well, that I can speak about her," said Amigorena, who said the couple had divorced in 2006 after eight years of marriage.

Gayet, 41, has not spoken publicly about the allegations published on Friday in Closer magazine that she had regular trysts with the president in a borrowed apartment close to his official residence.

Mr Hollande released a statement saying he deplored what he called an invasion of his privacy, but did not deny the affair allegations. He is under growing pressure after it emerged that his partner of several years and de facto First Lady, Valerie Trierweiler, had been hospitalised with stress.

Amigorena, with whom Gayet had two children, said his ex-wife was a "a wonderful actress who works hard, a mother who takes care of her children".

Asked about security concerns raised over the apartment where the couple met in secret, Amigorena said it had been lent to them by Emmanuelle Hauck, the actress mother of one of his children's schoolfriends.

Hauck was the girlfriend of Francois Masini, who reportedly had close links to the Corsican mafia and was shot dead on the island in May last year.

Before that she was married to actor Michel Ferracci, who has also been linked by the French media to the mafia. Ferracci got an 18-month suspended sentence in November for his role in money laundering.