The McCartney kid who is backing up her father the most is fashion designer Stella. Stella has been so incensed by the claims that Heather Mills has made against her father that she may be unintentionally threatening her pregnancy. The source said, "What [Heather is] doing to Stella's dad is really getting to [Stella]. Her blood pressure is very high, not something you need in the latter stages of a pregnancy."

One evening after discussing the pending divorce, Stella was filled with rage. She screamed upon hearing that Heather had claimed that Paul had beaten her mother, Linda. She allegedly yelled, "I'm going to kill that bitch! I can't believe what she's doing! I'm going to kill her! I told you she was a bitch. Why did you marry her? She's been a manipulative cow from day one. The cow won't be happy until she destroys all of us - and our memories of our mother.'"

Stella grew so angry that she was convinced that she needed to confront Heather right away. The insider says, "Paul kept pleading with her to calm down - but she couldn't. She wanted to go straight to see Heather, but he said, 'You can't go anywhere in that state'. He had to stand in front of the door and stop her. He was pleading with her. It was a heartbreaking scene."
Stella has disliked Heather since long before she married her father. The feeling was mutual and the two women reportedly made a pact not to speak with each other. In the weeks before Heather and Paul announced their split, Stella allegedly told her father, " I don't want to bring my child into this world with [Heather] as a grandmother. She's a bitch from hell."