Ellen DeGeneres, Louis C.K., Kelly Osbourne and Others Mourn the Loss of Joan Rivers

Joan Rivers has died at the age of 81.

She died today, one week after arriving at a New York City hospital last Thursday.

"It is with great sadness that I announce the death of my mother, Joan Rivers. She passed peacefully at 1:17pm surrounded by family and close friends," her daughter Melissa Rivers said in a statement to ABC News.

Read: Joan Rivers Dead at 81: Inside the Comedian's Close Relationship With Her Daughter, Melissa

Joan Rivers Hospitalized After Cardiac Arrest

The loss of a legend like Rivers cuts across so many generations and so many cultures, whether you are a fan of her comedy or not.

Even Barbara Walters added today on ABC News that if Rivers could see the outpouring of love for her, "she would have died smiling."

"I feel very lucky that I knew Joan Rivers and I feel very sad that she's gone. She was a great comedian and a wonderful person. I never saw someone attack a stage with so much energy. She was a controlled lightning bolt," Louis CK said via a statement.

Amy Poehler added, "What a full life. Every woman in comedy is indebted to her. She was there at the beginning and funny to the end. RIP Joan."

Other celebrities from the likes of "Fashion Police" co-host Kelly Osbourne to John Stamos to other comedians like Ellen DeGeners took to Twitter to share their condolences and their memories of the comedian, who first rose to fame all the way back in the 1960s and has been making people all over the world laugh for more than five decades.