If the grapevine is to be believed, singer Beyonce Knowles is cheating on her husband Jay-Z. She is reportedly having an affair with her bodyguard Julius De Boer.

Jay-Z, who married Beyonce in 2008, is said to be suspicious about her close relationship with Boer, reports showbizspy.com.

“Jay definitely thinks that there was and may still be something romantic going on between Bey and Julius. He wanted to fire Julius last February, but Beyonce said- ‘Julius isn’t going anywhere’,” said a source.

In 2009, Knowles, 32, and Boer were spotted leaving a hotel. Boer’s lips were stained with the singer’s signature red lipstick.

Despite being subject to numerous cheating rumours himself, Jay-Z is jealous of his wife’s friendship with her bodyguard.

“They’ve spent a lot of time together behind closed doors. He’s even stayed in her hotel room,” added a source.