Mekia Cox is an American actress and dancer, known for her recurring role as Sasha in the second and third seasons of The CW drama 90210, Dr. Robin Charles in Chicago Med, Nyla Harper in The Rookie, and her role as a dancer in the Michael Jackson concert series This Is It and the related film Michael Jackson's This Is It. In 2010, she assumed a supporting role in the NBC spy drama Undercovers. She is also known for her role as Princess Tiana in the ABC fantasy drama Once Upon A Time and for her role as Detective Nyla Harper in the ABC police drama The Rookie As a youth, Cox had a history of dance and theater training experience. Much of her early work was associated with Universal Studios and Nickelodeon. She continued to train in the performing arts in high school and college. Subsequently, she toured nationally in stage productions of musicals, including Fame.