Trouble is brewing for hip hop’s hottest couple -Jay Z and Beyonce. And that trouble is being caused by one of Jay Z’s newest artists, Rihanna. Rumors are beginning to circulate that Rihanna is becoming uncomfortably close to her mentor Jay Z. And that closeness reportedly bothers Jay Z’s longtime girlfriend Beyonce. As one entertainment insider tells us, “Rihanna is desperately trying to steal Beyonce’s look, her style, and even her sound … I wouldn’t be surprised if now she’s trying to steal Beyonce’s man.” At a recent NJ Nets game, Beyonce’s frustration boiled over. According to a fan seated near the couple, Beyonce lost her cool when Jay Z received a 15 minute telephone call from Rihanna. Beyonce reportedly yelled out “why do you keep talking to her” and stormed out of the arena before Jay Z had a chance to explain. Sources say Beyonce may truly have something to worry about. Last month, while Beyonce was in Los Angeles accepting a star on Hollywood’s Walk of Fame, Jay Z was reportedly in New York City wining and dining Rihanna. While the two did attend a series of business meetings, they also had dinner for two at Cipriani’s and later that evening the pair was spotted entering one of the private rooms at Jay Z’s 40/40 club. Our spy tells us that Jay Z and the young singer were all alone in the screened off room for more than four hours. Source: Mediatakeout.com