R&B superstar Usher is opening up about his failed marriage and custody battle with his ex-wife Tameka Foster in a tell-all interview with Oprah Winfrey. The Yeah! singer has previously refused to go into detail about the split, and insists his candid chat with the TV titan will be the one and only time he will discuss his personal troubles. The interview will air in the U.S. on Oprah's Next Chapter on Sunday (16Sep12).