Demi Moore has reportedly warned Mila Kunis to stand her ground.
The two actresses share a common bond in the form of Ashton Kutcher.
Demi, 51, married the Two and a Half Men star in 2005, before splitting with him following allegations of his infidelity.
Mila is now rumoured to be engaged to the 36-year-old actor, following a friendship that's spanned more than 15 years. She was recently spotted out wearing a diamond on her ring finger fuelling speculation that the couple are soon to wed.
"Mila and Demi have always got on OK. But that all deteriorated when Demi told Mila she mustn't take any nonsense from Ashton - and that she should be wary of every time he spends the night away from home. It made Mila feel awful," a source revealed to Britain's Now magazine.
Those close to the showbiz couple say Demi has reached out to 30-year-old Mila following media speculation that the Ted actress is pregnant with Ashton's child.
The advice hasn't gone down too well though, and Mila is said to be hurt that Demi is questioning Ashton's feelings for her.
"Mila knows Ashton loves her, but it's not nice to hear Demi's concerns. He's doing everything to show her he's devoted," the source added.
Demi and Ashton's marriage broke down in 2011 following allegations that he had bedded 22-year-old administrative assistant Sara Leal.
Sara has previously offered her own words of advice to Mila, telling her to be careful.© Cover Media