Joan Rivers remained on a life-support machine and was still in serious condition Monday, Sept. 1, at Mount Sinai Hospital, as doctors are expected to assess the extent of damage to her brain Tuesday after bringing her out of a medically induced coma, New York Daily News reported.

A source told the newspaper that a taping for "Fashion Police," a talk show co-hosted by the 81-year-old legendary comedienne, has been canceled. The E! program was supposed to shoot in New York this week in conjunction with Fashion Week, but due to Rivers' condition the taping has reportedly been halted.

Doctors at Mount Sinai Hospital started bringing Rivers out from her medically induced coma Sunday, Aug. 31, as her only child, Melissa Rivers, monitored how her mom will respond.

"The waking-up process has begun and will take until Tuesday," another source close to the family told New York Daily News. "There is real concern that the part of the brain that controls motor skills may have been compromised, leaving her as either a vegetable or in a wheelchair."

"Everyone is shocked that this happened," a source told Us Weekly, noting the Rivers was in great condition Wednesday night, Aug. 30, before she underwent a throat surgery the following day at a private Upper East Side clinic. "She's a strong woman, people aren't giving up hope, but it's very serious right now," the insider added.

Meanwhile, stars who have worked with Rivers expressed their support and prayers for the comedienne via Twitter.

"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," Kelly Osbourne tweeted Friday. Osbourne, who co-hosts the "Fashion Police" with Rivers, called the comedienne her "honorary" grandmother, according to Los Angeles Times.

"Praying for @Joan_Rivers and @MelRivers.  Even though Joan's the strongest woman I know, every single prayer counts. I love you, Joan," fellow "Fashion Police" host Giuliana Rancic wrote on the microblogging site Saturday.

"We can't lose Joan. All love and healing wishes to Her Majesty Joan Rivers- being ripped a new one by you is an honor to be treasured, "Girls" star Lena Dunham posted on Twitter Sunday.

"Sending love, love and more love to Joan," "Glee" actress Jane Lynch tweeted Monday.

"All paws crossed for @Joan_Rivers waking up today to a brand new day, awaiting her continued wit & spirit. #warrior #groundbreaker," fellow comedian Elayne Boosler wrote on Twitter Monday.