Kris Kross star Chris "Mac Daddy" Kelly has died at the age of 34. The rapper was found unresponsive at his home in Atlanta, Georgia on Wednesday and transported to Atlanta Medical Center, where he was pronounced dead, a representative for the Fulton Country Medical Examiner tells Billboard.com. The cause of death is not yet known and an autopsy is expected to take place on Thursday. Stars flocked to pay tribute to Kelly as news of his death broke, with Timbaland and Big Boi among the first to offer their condolences. R&B star Monica lamented, "Chris Kelly, may the peace...