Justin Bieber might not be much of a mama's boy after all.

Justin apparently screamed and threw a "hissy fit" when his mother, Pattie Mallette, asked him to be on the cover of her memoir, according to Radar Online.

“When Justin’s mom initially signed her book deal it included an agreement that Justin would appear on the cover with her, but she signed this deal without his consent,” a source says.

“When things with her book finally started coming to fruition, she approached him about being on the cover and he threw a massive hissy fit," the source adds. "Justin felt like it was unfair to him.”

Things between Justin and his mom got so heated that Justin's manager, Scooter Braun, actually had to break it up.

“It was literally a screaming match in [Justin's] dressing room, and Scooter had to step in and tell them that it was not the appropriate time or place,” says the insider.

Eventually, Justin agreed to help promote the book, Nowhere But Up, which details Pattie's battle with drug and alcohol addiction — but he still wouldn't be on the cover.

"He finally broke down closer to the release of the book and agreed to do a press junket with her for the big outlets to promote it, but the whole thing was so awkward and uncomfortable," the source continues.

And here we thought you weren't supposed to judge a book by its cover anyway.

Source: Radar Online