Aerosmith rocker Steven Tyler has admitted his dependency on pain relief medication sent him into rehab.

The singer checked into a facility in Pasadena, California last month, prompting speculation he had slipped from sobriety, 20 years after he kicked hard drugs.

Tyler later revealed he was in rehab on doctor's orders because of a foot injury.

But he has since confessed he was fighting a dependency on pain and sleep medication.

He says, "To have your feet done, to have your leg done, you have to be on narcotics.

"You have to be on sleep aids at night. I don't know about (bandmate) Joe (Perry), but I was off and running and I didn't like the me that was me."