Singer Jay Z has apparently warned singer Chris Brown not to hurt Rihanna again or he will be in a big trouble. Brown, Rihanna dated each other in 2008 before parting ways in 2009 after the former was accused of physically assaulting the “Umbrella” singer. Jay Z, known to be Rihanna`s mentor and brotherly figure to her, called the couple for a concert but ambushed Brown for a little man-to-man talk. “He invited them as a couple to his concert in New York and backstage he called Chris to one side and told him if he hurts Rihanna, whether emotionally or physically, it`s over for him,” thesun.co.uk quoted a source as saying. “He`ll ensure it will result in the end of his career,” the source added. Meanwhile, Jay Z, 42, has given Rihanna a green signal regarding Brown and told her to follow her heart. “Jay Z told Rihanna that if Chris is truly making her happy, then to go for it,” the source said.