The author of an unauthorized biography of Beyoncé says that despite rumors that Jay Z cheated, Bey would never tolerate it.

One bombshell revealed in J. Randy Taraborrelli’s book “Becoming Beyoncé” is about a rumored Jay Z fling with protégée Rihanna when she was just 17.

“It was total fiction,” the author told “Entertainment Tonight,” claiming a publicist concocted the tale to boost Rihanna’s career. But, “Beyoncé didn’t know what to make of this, and it actually ended up breaking them up for a time. They spent maybe a year apart from each other because Beyoncé just wasn’t sure of what to make of the situation with Rihanna.”

Now, “It’s safe to say that Rihanna and Beyoncé are friends.”

He adds RiRi was partially to blame for Jay’s infamous elevator fight with Beyoncé’s sister Solange in 2014.

“People told me that there was a whispered argument that night having to do with Jay wanting to go to a party [for] Rihanna,” he said. “Beyoncé did what Beyoncé does. She laid down the law . . . it was a whispered married couple’s argument that would’ve gone by completely unnoticed had not Solange overheard it.”

At that time, after the Met fashion gala in New York, Jay Z told Beyonce that he wanted to go alone to the party organized by Rihanna. However, his sister-in-law Solange Knowles, who had a “cow-lung” personality, could not accept this. Solange questioned her brother-in-law: “Why don’t you go home?”. After a few words, Solange rushed at Jay Z and started punching him while Beyonce stood still and watched. This scuffle scene was accidentally recorded on camera and leaked out.