With the estranged wife of Sir Paul McCartney, Heather Mills, having reportedly asked for $50 million, this divorce could be one of the most expensive divorces the world has seen.

After four years together and one child from their union, the couple announced they were calling it quits this week.

McCartney is estimated to be worth $1.5 billion, and it is believed he and Heather have no prenuptial agreement. On his official Web site some time ago, McCartney had dispelled rumours that Mills was only after his fortune — but if they truly divorce, Mill could stand to make off with a king’s ransom.

If a divorce becomes final, McCartney will join an exclusive club of famous ex-husbands whose divorces cost them big-time.

Here are some whose cost them really big time.

Raiders of the Lost Ark and Schindler’s List director, Steven Spielberg, divorced his first wife, actress Amy Irving, after four years of marriage in 1989. The split was amicable, but the price was exorbitant, as he reportedly forked over $100 million.

Another major Hollywood director, James Cameron, made his Terminator leading lady Linda Hamilton his fourth wife in 1997. But their romance hit an iceberg during the filming of Titanic, and Cameron was reportedly forced to sink more than $50 million of his earnings.

And it was Dances with Lawyers for Kevin Costner, when the star was ordered to pay his college sweetheart and wife of 16 years, Cindy, a hefty $80 million after their relationship saw no way out in 1994.

The magic number was a reported $90 million for Stars Wars star Harrison Ford when he went solo from ET the Extra-terrestrial screenwriter Melissa Mathison after two decades of marriage to date Ally McBeal star Calista Flockhart. And when Tom Cruise’s marriage to Nicole Kidman became a Mission: Impossible, he reportedly also coughed up $90 million of Collateral when they split in 2001, just short of 10 years together.

It was love on the rocks for Neil Diamond, whose 1995 break up with second wife Marcia topped the charts to the sweet tune of $150 million! But the No 1 most expensive celebrity divorce is that of Rupert and Anna Murdoch. One of the world’s richest men, the billionaire media mogul paid Anna a reported $1.7 billion after 32 years of marriage. Rupe then married one of his employees, Wendy Deng, just 17 days later!