Denise Michelle Crosby (born November 24, 1957) is an American actress and model known for portraying Security Chief Tasha Yar mainly in season one of Star Trek: The Next Generation, and Yar's daughter, the half-Romulan Commander Sela, in subsequent seasons. She is also known for her numerous film and television roles and for starring in and producing the 1997 film Trekkies. (Via Wikipedia)