While 15-year-old Rocco, whose father is Guy Ritchie, deleted his account on the photo-sharing app earlier this year, a new account set up in his name describes him as a "son of a b****", reports dailymail.co.uk.
The account is private but features a closeup of Rocco's face as the profile picture. It is not clear if the Instagram page has been set up by him or not.
Madonna and Guy are currently locked in a custody battle over Rocco, who left his mother's world tour last year to live in London with his father.
"If this is his new account then clearly comments like this show he's in a delicate place and highlights the fact he needs to be in an equally supportive relationship with both parents,� said a source.
"The fact it has been set up at all, even if it is just a prank by one of his friends, shows how public their feud has become. For Madonna, it is proof their relationship needs to get back on track as soon as possible,� source added. (IANS)