Mila Kunis new relationship may have Demi Moore upset.

Ashton Kutcher's new girlfriend Mila Kunis and a fight over money may spell out a nasty divorce fight between Ashton and Demi Moore.

Demi is reportedly unhappy about Mila and Ashton's new relationship and Kutcher is unhappy over the split of assets, a report has claimed.

Ashton has already moved on from his wife and is reportedly living with his new girlfriend Mila, whom he has known for 14 years as they previously starred in the hit comedy series 'That 70s Show' together.

Demi and Ashton - who separated last November after six years of marriage following the 'Two And A Half Men' star's affair with 22-year-old San Diego-based administrative assistant Sara Leal - are said to be locked in a bitter battle over their enormous fortune.

A source told The New York Post: ''(They) are trying to negotiate a settlement out of court and out of the public eye. They still haven't reached an agreement over money, because Ashton earned substantially more during the final years of their marriage, but he doesn't want to pay a large settlement.''

The 34-year-old actor - who is currently the highest paid star on TV for his role on 'Two and a Half Men' - is worth $138.5 million, while Demi is worth $150 million.

Another source close to the pair said: ''The discussion could boil over into a public court battle.''

Ashton was previously said to be refusing to budge on the financial terms of their separation and how they should divide their assets.

A source said the actor is ''so cheap'' and is refusing to sign off on the paperwork so they can finally go their separate ways.

© Bang Showbiz