Jay-Z is allegedly at "the end of his tether" with Rihanna.
The rapper runs Roc Nation, which is the label the singer is signed to.
He is said to be concerned by the controversy surrounding the Barbados-born star recently, including wild partying and her late arrivals for performances while on the Diamonds World Tour.
As Rihanna's mentor, Jay-Z has apparently warned her to calm down, but his advice seems to be falling on deaf ears.
"Jay-Z is at the end of his tether. Despite numerous interventions with Rihanna and intense heart-to-heart meetings, Jay-Z despairs that she isn't taking his advice seriously," a source told the latest edition of UK magazine Look. "But there are only so many times you can tell someone something, and they ignore you, before you stop. It's hard for him as he loves Ri dearly and wants to help her, but she won't listen right now."
In a last ditch attempt to tame her worrying behaviour, Jay-Z is now attempting to schedule another face-to-face meeting with his protégée.
He reportedly hoped they could catch up while both in the UK for the recent Wireless festival, although it is not known whether this meeting took place.
"He was trying to coordinate their diaries so they could chat. He wants her to enjoy herself but he worries about her," the source finished.
This follows recent reports claiming Rihanna received a written warning from Roc Nation about her antics.
In June a source revealed that concerns had been raised with the star already.
"Everyone can see Rihanna's not behaving herself. Fans have paid hundreds of pounds for tickets and she's regularly showing up hours late," an insider sighed. "Then she often gives lacklustre performances where she even forgets her words at times. They issued a written warning which was emailed to Rihanna."