The troubled actor, who appeared on Celebrity Rehab, is reportedly in critical condition

By Dahvi Shira
Updated May 18, 2011 07:15 PM
Kathy Hutchins/Hutchins Photo

Celebrity Rehab alum Jeff Conaway is back in the hospital following an apparent overdose.

The Taxi star, 60, who has had a longtime public battle with cocaine, painkillers and alcohol, is in critical condition at Encino Hospital Medical Center unconscious with pneumonia, according to the Los Angeles Times.

The troubled actor is also known for his role as Kenickie, the suave T-Birds member who starred in Grease alongside John Travolta and Olivia Newton-John.

In January 2010, Conaway fell down a staircase and suffered a broken hip, a broken arm, a fractured neck and a brain hemorrhage.