Mendes triumphed at 2000's Oscars

"Yes, we are having a relationship. It's early days, and we are very happy," he told the Daily Mail newspaper.

But American Beauty director Mendes, who has been linked with a string of stars including The Mummy actress Rachel Weisz, denied that he played a role in ending the 26-year-old's marriage.

Speaking in Los Angeles, he said: "I was very careful to ensure that I was not endangering her marriage.

"Indeed, it was already over, and I came along well after.

"I am delighted to express my delight at being with Kate."

The 35-year-old said Winslet and Threapleton were having an "on-going, amicable discussion on how to bring up their daughter".

Winslet married Jim Threapleton in 1998

The couple, who celebrated the birth of their first child, Mia, last year, married in 1998.

At the time of their split, a spokesman for the actress stressed that no other parties were involved in the "amicable and respectful separation".

The separation followed reports of rows between the couple for several weeks.

Winslet, who recently starred in the code-breaking tale Enigma, met Threapleton during the filming of Hideous Kinky in Morocco in 1998.

Winslet "wept a sea of tears" when the couple married in Reading, Berkshire, in November 1998.

Low-key

It was a low-key event at which friends and family, including actress Emma Thompson, ate sausage and mash at the Crooked Billet pub during the reception.

She went on to become an international celebrity after appearing in the blockbuster movie Titanic, and followed up that success with a host of appearances in smaller, low-key movies.

After their wedding, Winslet spoke often of putting her marriage first.

Around the time of the split, the star told In Style magazine how her career came second to her home life.

"An actor's happiness has to come from something other than work," she said. "I know we're very lucky."

She said having a baby had "strengthened the relationship, although there are highs and lows, and at times it's tough".