Hewitt and Clijsters were due to have married next February

The Australian and Belgian had been due to marry in February but a statement on Clijsters' website said their engagement was over.

It said the couple had "jointly decided to put an end to their relationship for private reasons".

The statement added: "Both of us distance ourselves from the malicious gossip which inevitably surfaces in this kind of situation."

The relationship between the 23-year-old Hewitt and the 21-year-old Clijsters began after they met at the Australian Open in 2000.

Hewitt's feisty nature is in contrast to Clijsters' reputation as one of the nicest players on the tennis circuit but their romance flourished.

MIXED DOUBLES Jimmy Connors/Chris Evert Got engaged in 1974 but split up a month before their planned November wedding. Evert went on to marry - and divorce - former British number one John Lloyd. Andre Agassi/Steffi Graf Two of the most famous players in tennis history got together in 1999 and tied the knot in 2001. They have two children.

The two former world number ones come from sports-mad families - Clijsters' father was a professional footballer while Hewitt's father played Australian Rules.

They spent time together whenever their busy schedules allowed and were regular fixtures at each other's matches in Grand Slams where the men's and women's tours play alongside each other.

And they got engaged on a romantic boat trip around Sydney Harbour last December.

Clijsters made no secret of her desire to take a career break in the not-too-distant future to have children and her ongoing wrist injury led many to speculate that would be sooner rather than later.

A wedding date was set for February but now comes the news that the pair have ended their relationship.

Andre Agassi and Steffi Graf may edge Hewitt and Clijsters when it comes to fame, but Graf had already retired by the time their relationship became public.

Perhaps a more relevant precedent for Hewitt and Clijsters was the romance between Jimmy Connors and Chris Evert back in the 1970s.

The American pair got engaged back in 1974 when Evert was 19 and Connors 21.

When both won Wimbledon that year and danced together to "The Girl That I Marry" at the famous champions' ball, it seemed like a match made in heaven.

But their relationship foundered and they split up less than six months later.