Rapper Eminem is officially back in the studio and working on his new album, a label source tells EW.com. Bishop Lamont, another protege of Eminem and Dr. Dre, said, "Em is excited. He's been quiet too long, and he's got a lot to get off his chest." It's been four years since Slim Shady released his last studio album, Encore. In the time since, one of Eminem's closest friends, rapper Proof, was shot and killed, leaving Em emotionally devastated. There were also reports late last year that the 8 Mile star suffered a mild heart attack, thought people close to him said he just had the flu. "He went through what he had to go through, and now he's been able to take all the pain and stress and put it out in his music," Lamont added. No release date for the Marshall Mathers' fifth album has been announced.