Joan Rivers' condition at New York's Mount Sinai Hospital remains critical after she "suddenly stopping breathing" while under an operation for her vocal chords.

Rivers was hospitalized Thursday and was put by doctors into an induced coma to prevent her condition growing worse.

Rivers' only daughter, Melissa Rivers, flew in from California to show support for her ailing mother and continues to thank everyone for keeping her mother in their "thoughts and prayers."

Stars who have worked with Rivers also expressed their concern and sincere prayers for the comedienne, including Kelly Osbourne, Girls star, Lena Dunham, and E! News host, Giuliana Rancic.

"4 the first time in years I got down on my knees & prayed tonight! I encourage U 2 do the same, 4 @Joan_Rivers my grandma! #inconsolable" Osbourne wrote on her Twitter account on Friday.

Osbourne co-hosts the E! Show 'Fashion Police' with Rivers, where they praise and scrutinize the outfits worn by celebrities.

Osbourne calls Rivers as her "honorary" grandmother, as reported by website, LA Times.

"Even though Joan's the strongest woman I know, every single prayer counts. I love you, Joan," wrote Giuliana Rancic via Twitter on Saturday.

"We can't lose Joan. All love and healing wishes to Her Majesty Joan," said Lena Dunham in a Twitter post on Sunday, Dunham who has previously said that one of her comedic idols is Ms. Rivers.