A new tell-all book claims Beyoncé once dumped rap mogul husband Jay Z at the height of rumors he was cheating with hip-hop star Rihanna.

Radar Online reports celebrity journalist J. Randy Taraborrelli claims in the new unauthorized biography "Becoming Beyoncé" that around 2005 the "Bonnie and Clyde" duo began incessantly fighting over her "obsessive dedication" to work.

"He felt that she was too concerned with [work] and overwhelmed by it," a source said of the 34-year-old "Drunk in Love" singer. "She also had a tendency to become moody and defensive when under great work pressure, and it had begun to drive a wedge between her and Jay. The two broke up for a time during that year. She flat-out told him she needed a break."

During that time, Jay allegedly began romancing a then 17-year-old, still up-and-coming Rihanna. While Taraborrelli notes a former member of Rihanna's camp later claimed the relationship was made up to attract attention, the stories made their way to Beyoncé, who seemed to find some validity in them.

"Beyoncé wasn't sure she could trust Jay when it came to his adamant denials," the book claims. "She couldn't help but be skeptical."

In time, all the tension exploded into a showdown between the couple that played out at Jay's 40/40 club in New York.

"All that was heard ... was Rihanna's name uttered several times, before Beyoncé stood up and stormed off," according to Taraborrelli.

About a year or so later, the two found their way back to each other, and by 2008, they were man and wife.

But even after that, Taraborrelli claims Rihanna remained a sore subject for the hip-hop royal couple, and the 2014 Met Gala elevator brawl between Jay and sister-in-law Solange stemmed from his suggestion that the couple attend a party hosted by the "Diamonds" singer.

The book is scheduled to hit bookstores later this month.