Pals for life.
"My heartfelt thoughts are with his family and loved ones at this very difficult time," Travolta added.
Conaway began using drugs in the mid-1980s, and by 2008, he appeared on VH1's "Celebrity Rehab with Dr. Drew," where he sought treatment for addictions to cocaine, painkillers and alcohol.
"I'm saddened to report [Conaway] has succumbed to his addiction," Dr. Drew Pinsky tweeted Friday. "Thus far we have no evidence of an intentional overdose."
Pinsky added: "Please continue to send your well wishes and prayers."
Eva Longoria wrote on the microblogging site: "My fav Grease quote is, 'A hickey from Kinickie is like a Hallmark card.'"
Conaway passed away at 10:30 a.m. Friday morning, his manager, Phil Brock, confirmed to Us Weekly in a statement. "He was taken off life support yesterday afternoon. His sisters, nieces, nephews and ministers were by his side when life support was removed."
The actor, 60, was hospitalized on May 11 for what was initially thought to be a prescription drug overdose. It was later revealed that he was suffering from pneumonia and sepsis, a dangerous blood infection. He remained in a comatose state for over two weeks until his death.
In the 1978 classic musical, "Grease," Travolta, 57, played Danny Zuko, and Conaway played his confidant, Kenickie. Conaway was even married Rona Newton-John, the sister of his "Grease" costar, Olivia Newton-John, from 1980 to 1985.
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