The source went on to claim the drama began when the 27-year-old actress wouldn't let her soon-to-be mother-in-law "be any part of the planning, and she wouldn't clue Victoria in on anything. Communication was minimal."
According to the source, the rocky relationship between the pair is resulting in a wall between the Beckhams and their son as it's "non-stop petty drama".
"They haven't spoken to him much in the last few months," the source said before adding they suspect the heiress is "suffering from a little jealousy" about her mother-in-law's icon status.
It comes after fans noticed the two have been "ignoring each other" for months on social media and quickly started speculating there could be a bitter secret hiding in plain sight.
According to the Daily Mail, a "family insider" raised suspicions when they refused to either confirm or deny the theory. Instead, they told the news outlet, "People constantly speculate about relationships β we don't really care as it's just silly."
Another source fuelled rumours when they said the Peltz family's attitude towards brand Beckham could be to blame for the distance.
They said: "There is a feeling that the Peltzes rather turn their noses up at the Beckhams β¦ the way that they do things, and their celebrity profile.
"Meanwhile, the Peltz clan has really embraced Brooklyn. There is a feeling that Brooklyn is now all about the Peltz family and not the Beckhams."
Suspicions only heightened when Beckham skipped out on the family's recent European mega-yacht vacation to celebrate his wife's grandmother Bunny's 94th birthday instead.
The actress later flaunted her husband's activities on her Instagram account and posted a video of the aspiring chef reading out a birthday card he wrote for the matriarch.
"Happy birthday, I love you so much and I'm so honoured to be here on your birthday," The young Beckham said in the heartfelt video. "You're so amazing and you look so gorgeous today. Thank you for letting me into your gorgeous family."
The actress captioned the post, "second slide melts my heart into a puddle ~ look at her face".
"Celebrity wedding of the year"
The young couple tied the knot earlier this year with a three-day extravaganza which earned the title "celebrity wedding of the year".
They chose to hold two ceremonies - one Jewish, to honour Peltz's father, Nelson, and another Catholic, for her mother, Claudia. They invited 300 guests, including actress Eva Longoria, tennis superstar Serena Williams and former Spice Girl Mel C.
Peltz's father, a financier, reportedly insisted on covering the entire cost of the celebrations. According to the Sun, Peltz senior is said to be worth NZ$2.55 billion, while the Beckhams are worth a comparatively small $722 million.
