'Duck Dynasty' Star John Luke Robertson Welcomes Baby No. 2 With Wife Mary Kate
's John Luke Robertson and his wife, Mary Kate, are now a family of four! John Luke revealed via Instagram on Monday that Mary Kate has given birth to their second child, a baby girl, whom they've decided to name Ella.John Luke and Mary Kate have been married since 2015 and are also parents to their 1-year-old son, John Shepherd. The couple shared pictures of their newborn daughter on Instagram.«Welcome to the world baby Ella!» John Luke, 25, wrote.