Sharon Osbourne, her daughter Kelly, Lena Dunham, Anna Kendrick, Ellen DeGeneres, Ariana Grande, Ryan Seacrest and Whoopi Goldberg are among the stars to pay tribute to Joan Rivers.

The Fashion Police host passed away yesterday in hospital following surgical complications, and Hollywood has since taken to social media sites to remember the 81-year-old comedienne.

American Idol host/the man responsible for The Kardashians Ryan Seacrest sent his condolences to Joan's family while recalling the 'treat' he had bumping into her in the hallways of E! network's studio.

He tweeted: "She was trailblazing. Hysterical. Thoughtful. We'll miss you immensely Joan. It was a treat running into Joan in the hallways at E!...she was always on... always a riot. Our thoughts are w/ you & your family (sic)."

Whoopi reacted the news with a crying-faced emoticon, before saying goodbye to the comedy legend.

She wrote: 'My friend Joan Rivers has passed away once again to quote Billy Crystal... There are no words. Bon Voyage Joan (sic).'

Lena Dunham also responded to the news, tweeting: "Watching Joan Rivers do standup at age 81 was incredible: athletic, jaw-dropping, terrifying, essential. It never stopped. Neither will she."

Rumer Willis added: "I feel so blessed to have had the pleasure of chatting with Joan Rivers before she passed. What an incredible woman. Your humor and wit have changed lives. RIP (sic)."

David Hasselhoff said: "Goodbye to the First Lady of comedy. A very sad day for the world. Love to Joan's family and deepest respects during this difficult time."

Dita Von Teese added: "Sad to hear of Joan Rivers' passing. A great lady. It was an honor to have a chance to spend a day with her once. (sic)."

Sarah Michelle Gellar said: "I am so sad. May I live my life as full as Joan Rivers did. Today is a sad day, but I will try and laugh to honour her."

Joan was rushed to Mount Sinai hospital in New York last Thursday after she went into cardiac arrest and stopped breathing while undergoing a routine operation on her vocal cords at the Yorkville Endoscopy clinic.

The blonde beauty was put into a medically-induced coma and was placed on life support.

Her daughter Melissa, 46, told fans yesterday (03.09.14) that her mother's condition was improving and she had been moved to a private room at the hospital, but remained on life support.

However, Melissa announced this evening that her mother had passed away at lunchtime surrounded by her friends and family.