Katie, 35, took to Twitter in a fit of rage last night (15 December) and ranted about 40-year-old Peter's festive plans with their kids, Junior and Princess, despite an agreement that he had got them.
The mum-of-four told her followers that Peter was having Junior, eight, and six-year-old Princess from Christmas Eve until New Year's Eve, meaning she, Jett and her eldest son Harvey would not see them.
Katie, who is married to stripper Kieran Hayler, also said she would not do the same once Peter and his pregnant girlfriend Emily MacDonagh have welcomed their unborn baby into the world.
I wouldn't do this to pete and deprive him and his newborn from seeing the kids for its 1st christmas— Katie Price (@MissKatiePrice) December 15, 2013
She added: "I wouldn't do this to Pete and deprive him and his newborn from seeing the kids for its 1st christmas."
Referring to 11-year-old Harvey, who called Peter 'dad' when the Australian pop star was married to her, Katie added: "Can someone remind him he has a son called Harvey that calls him dad or was that just for show too?"
Katie replied to one of her followers, who told her to "grow up", saying: "It's not me it's him and it's disgusting him not asking to see Harvey...been a year now he hasn't had him."
However, although Peter's rep had no official comment to make, sources close to the star have said that he is desperate to see Harvey, adding that they had agreed he could have Junior and Princess at Christmas.
"Katie had the children for the entirety last year," the source said. "Peter is desperate to see Harvey."
Their Christmas disagreement comes as Peter grieves the death of his brother Andrew, who passed away following a cancer battle exactly one year ago today.
The source added: "Peter is grieving today on the first anniversary of his brother's death."