Rihanna is going one-on-one with Oprah. After winning five Grammys and landing 11 No. 1 singles, the “Where Have You Been” singer returns to her native Barbados and discusses her journey to becoming one of the biggest pop stars on the planet on “Oprah’s Next Chapter.”  Watch a teaser of the episode, which will air on August 19 at 9 p.m. on OWN.