Brandy's pregnant sister-in-law has threatened to expose the R&B star as a fake after she attempted to silence rumours of a rift by insisting there is "nothing here but love".

The Boy Is Mine hitmaker hit headlines on Monday (19Mar18) after skipping the weekend baby shower for her brother Ray J and his expectant wife Princess Love, amid gossip suggesting the two women had fallen out.

Brandy and Ray J's mother, Sonja Norwood, was also absent from the gathering on Saturday (17Mar18), which was held hours before the 39-year-old singer was due to perform a concert in Virginia.

At the time, sources told TMZ.com they missed the baby shower after an argument with Princess Love over Twitter posts she had shared, appearing to hint at Ray J's infidelity, but Brandy tried to play down the drama by taking to Instagram this week to send the parents-to-be her best wishes.

"Congrats to my brother and sister on their Baby and Baby Shower... I'm very excited to be an Auntie," she wrote. "So sorry I missed this moment with the both of you..."

Brandy went on to insist she was "so glad" she was able to attend a gender reveal party they had arranged for 16 March (18), and seemingly addressed the family feud reports by stating, "There is nothing here but love and no matter what anyone says we are family and we will always be. Your beautiful bundle of joy will change our lives forever. Love you Prinky @princesslove and I love you infinity @rayj (sic)".

However, reality TV star Princess Love didn't appreciate the public show of affection and called Brandy out as she commented on the message, which quickly went viral.

"STFU (shut the f**k up) posting this," she raged, "I should post what you just text me (sic)".

Brandy didn't respond to her sister-in-law online, and instead deleted the post altogether.

Ray J has yet to weigh in on the controversy. He wed Princess Love in 2016 after a tumultuous relationship, and announced their baby news in November (17).

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