Katie Price was left furious after estranged husband Peter Andre invited one of her arch-rivals to their daughter's birthday party.
The British star was livid after learning fellow glamour model Chantelle Houghton - who she has publicly criticised in the past - turned up at the 'Mysterious Girl' singer's house to help Princess Tiaamii celebrate her second birthday and she is now worried the pair are going to start dating.
A source close to Katie - who also has a four-year-old son, Junior, with Peter, as well as seven-year-old Harvey from a previous relationship - told Britain's Daily Star newspaper: "She is terrified Chantelle could become Pete's girlfriend and start playing mother to her kids."
When questioned about Peter's growing closeness to Chantelle, Katie snapped: "There's no point asking. Goodbye!"
Chantelle has made no secret of her fondness for Peter since he announced his split from Katie in May.
She said: "Of course I'm attracted to him. Pete is an amazing guy - very hunky."
Katie - also known as Jordan - is working hard to repair her image after she was heavily criticised for her wild partying while on a recent holiday in Ibiza.
A friend said: "In Ibiza Katie went back to being crazy Jordan. But now she's realised it could affect her chances of getting the kids.
"She knows she's got to be sensible Katie Price, who's a good parent, role model and charity fundraiser. She knows she has to knock wild nights out on the head - for the time being at least."
Meanwhile, Sarah Harding has spoken out in support of both Katie and Peter, insisting she is refusing to take sides.
The Girls Aloud beauty - who was bridesmaid at their 2005 wedding - said: "It's so sad. I really hoped it wasn't permanent and wanted to get them back together. They have both been good friends to me in the past.
"I'm not going to be drawn into team Katie or team Pete."