Madonna's kids Lourdes and Rocco, who are working in two different departments of their mum's MDNA tour, are trying to out-do each other while working.
Lourdes, 15, is involved with the wardrobe department, while 11-year-old Rocco is on stage.
"Rocco and Lourdes have developed a really competitive spirit as they take up roles on their mum's tour," dailystar.co.uk quoted a source as saying.
"Lourdes is in charge of fashion and wardrobe and is responsible for picking outfits for at least 10 of the dancers. Rocco is doing a series of break-dancers and singing on a few tracks. Between the two of them, they are constantly involved in one-upmanship.
"Madonna has taken an army of helpers along with her for the children, including five nannies and eight private tutors. The cost must be absolutely phenomenal with their hotel bills, food and wages," added the source.
The family spat is reportedly causing more stress for the 53-year-old star than the pressure of performing.
"It's all working out completely differently to how Madonna had hoped it would go and is creating family scenes.
"The kids are already causing her a massive headache and she had originally planned for her other two children David and Mercy to join them at some point. She's close to tearing her hair out," said the source.
Of course it's not only family squabbles that Madge is involved in. The nipple and knicker flashing mum (in Istanbul and Rome dates of her tour, respectively) is in a very public feud with Lady Gaga, with the mother monster finally hitting back this week, calling the Express Yourself singer a "menopausal mom" and describing her flesh-flashes as "pathetic".