Joan Rivers was put into a medically induced coma on Thursday, according to a source close to the veteran comedian. She was listed as stable but was still in critical condition after falling into cardiac arrest while undergoing routine throat surgery.

A source close to Rivers told E!, "They were putting a scope down her throat to check her vocal cords. This was not major surgery." Rivers was under sedation at the time.

As expected, tons of celebrities are Tweeting messages of support for JOAN RIVERS. And not surprisingly, the best one came from a fellow comedian: JEFF ROSS, who you'd know from all those Comedy Central roasts.

He said, quote, "Don't worry folks, Joan Rivers won't die because she refuses to follow Robin Williams."

He later added, quote, "I'd pray to God for her healthy recovery but she is my God."