When Rihanna performed at the NBA All-Star Game last month, it was apparent her typically stellar vocals were a bit on the weak side, as the singer was reportedly suffering from a bout with bronchitis. The singer hasn't really taken any down time to deal with her health problems by easing up on her appearances, which has caused longtime mentor and friend Jay-Z to take notice.

According to Look Magazine (as quoted by MTV UK), Jay-Z is worried that the 23-year-old is being overworked and that her current schedule is causing her health to deteriorate. "Rihanna's professional, works hard and stays away from drugs and alcohol, but Jay wants her to be careful," a source told the publication.

During the Grammy Awards in February, the 'S&M' songstress fell ill with bronchitis and laryngitis, yet still managed to perform despite the setback such sicknesses could cause her in the longrun. To help Rihanna get her vocals back in tip-top shape, the 'Empire State of Mind' rapper suggests she takes a much needed break.