LONDON - Formula One boss Bernie Ecclestone voiced surprise after his wife announced they were splitting, a report said Friday as experts predicted the divorce may be one of the most expensive ever.

A spokeswoman for Ecclestone's wife Slavica said Thursday that she had filed for divorce, but that seemed to come as news to the diminutive motor racing chief when he was asked about it by London's Evening Standard newspaper.

"Really? Oh... we will see. I didn't even know she had a PR company. You hear of things - I must find out," he said, adding that his wife had moved out of their London home because of noise from building works next door.

The couple have been married for nearly 24 years and are worth a reported 2.4 billion pounds (2.8 billion euros, 3.5 billion dollars), prompting lawyers to predict that any divorce settlement could break records.

Margaret Hatwood, an associate at law firm Thomas Eggar, said it has got "every chance of being the largest case ever" in English law.

Although she played down reports that Slavica Ecclestone, a Croatian former model, could get up to 50 percent of the fortune, she added that the length of the marriage could have a big impact on the case.

"It's going to make a significant difference because one of the factors the courts look at is the length and that's one reason why Heather Mills did not get so much," she told AFP.

Mills, who married former Beatle Sir Paul McCartney in 2002, was awarded 24.3 million pounds (48 million dollars, 30.8 million euros) in a divorce accord agreed in March after lengthy and acrimonious negotiations.

Simon Bethel, of law firm Mills and Reeve, said it could be complicated to put a figure on the extent of their wealth.

"Part of the family wealth is already reputed to be controlled by Mrs Ecclestone through a Jersey-based trust fund, and thus the area of dispute may revolve around quantifying the value of Mr Ecclestone's motor racing empire - that rather modest concern known as Formula One," he said.

Media reports suggest that Slavica Ecclestone, 50, moved out of the family home in Chelsea, an affluent part of west London, the weekend of the Brazilian Grand Prix at the start of this month which saw Lewis Hamilton become F1 world champion.

Bernie Ecclestone, 78, is chief executive of Alpha Prema which owns Formula One. Last year he also took over Championship football club Queens Park Rangers with Renault team boss Flavio Briatore.

The couple, who married in 1985, have two daughters, Petra, 19, and Tamara, 24.