John Travolta has paid a sweet tribute to his daughter Ella Bleu Travolta on her 21st birthday. It has been a heartbreaking year for his family after the passing of his wife and mother of his children, Kelly Preston.The 67 year old star penned a heartfelt post to his daughter as she celebrated her milestone birthday, writing: “Happy 21st birthday to the most beautiful, kind, human being and artist I know.