However, their stubbornness is now indicating that they may finally have to battle their case in the court.
"It could well go to trial because they are both quite stubborn," Times Online quoted one lawyer as saying.
The couple's case is scheduled for a five-day hearing next February, to be presided over by family High Court Judge, Justice Bennett.
"Five days is only a relatively short hearing but then the issues are fairly straightforward and it was a short marriage," the lawyer added.
McCartney and Mills are taking the services of Fiona Shackleton and Anthony Julius, respectively, the lawyers who fought the divorce case of the Prince and Princess of Wales.
Source: ANI
LIN/C