Los Angeles - Kelly Osbourne is "completely heartbroken" over the death of Joan Rivers.
The 29-year-old beauty paid tribute to her Fashion Police co-star in a heartfelt message following the comedienne's passing on Thursday evening.
She took to her official Facebook page to share her feelings.
Kelly - who has worked with Joan on the show since 2010 - also reached out to the 81-year-old star's only child, daughter, Melissa, 46, and grandson Cooper, 13.
She went on to shared a petition that has started to declare 4 September national Joan Rivers Day as well as the first time she met the comedienne icon.
Melissa announced last night that her mother had died at Mount Sinai hospital surrounded by her friends and family following a week on life support.
Joan had been rushed to the medical center last Thursday after she suffered cardiac and respiratory arrest while undergoing a routine operation on her vocal cords at Yorkville Endoscopy clinic.