Sir Paul McCartney and estranged wife Heather have hired the same lawyers who represented Prince Charles and Princess Diana when they divorced 10 years ago.
Sir Paul and Mills met at a charity event in 1999
Lady McCartney, 38, has retained solicitor Anthony Julius, who acted for Princess Diana in 1996, winning a reported £17m settlement.
Sir Paul, 64, has chosen Fiona Shackleton, who represented Prince Charles, to argue his case.
The couple announced their separation in May after four years of marriage.
Their legal teams will be battling over Sir Paul's fortune, which is believed to be more than £800m.
The couple, who have a two-year-old daughter, Beatrice, blamed their break-up on press intrusion, and said they remained friends.
But a spokesperson for Lady McCartney said on Tuesday that Sir Paul had frozen their joint bank account and had complained about her removing three bottles of cleaning fluid from his home in Sussex.
Police were called to Sir Paul's London home on Monday after an incident involving his estranged wife.
The model and campaigner arrived at the property to find the locks to its gates had been changed.
Her security guard scaled the wall to let her in, prompting staff inside to contact the police.
Lady McCartney has played down the incident. "She was laughing about it," spokesperson Phil Hall told the Reuters news agency.