Joan Rivers died on Thursday at the age of 81 and fans were quick to tweet messages of sorrow. Among them were her Fashion Police co-stars Giuliana Rancic and Kelly Osbourne, who shared a sweet photo of the pair of them and some moving words. On Facebook she posted: 'I'm completely heartbroken by the loss of my beloved Joan. Not only was she my boss, she was and will always be my teacher, therapist, closest friend, inspiration and the only grandmother I ever knew. She was family and I will never forget her. 'Laughter will be difficult for a while but when I'm sad, lonely or upset all I will have to do is think of Joan and a smile will cross my face. Laughter is what she gave us and laughter is what she would want usto do in remembrance of her.' The 29-year-old, who is currently in hospital with pneumonia, added: 'Melissa and Cooper, my thoughts are with you and I love you both so much. Joan, thank you for taking me in and loving me as a daughter. I will mis...