CRITICAL: Grease Star in Coma After OD!

Former Celebrity Rehab patient Jeff Conaway is in critical condition in a California hospital after an apparent drug overdose. The 60-year-old actor, who starred as bad-boy Kenickie in Grease and as wisecracking Bobby Wheeler in the sitcom Taxi, "is in a coma and unresponsive at this time," his rep tells E! Online. Conaway, who opened up on reality shows about his addictions to cocaine, painkillers, and alcohol, has struggled with health problems in recent years.