Rocker Steven Tyler has become a secret guardian angel for staff at the fabled Betty Ford Clinic after seeking treatment there for a painkiller addiction in 2009.

The Aerosmith star checked into rehab after getting hooked on pills following foot surgery and though he was "a challenging patient" at the time, he has become a huge advocate of the California treatment facility, even agreeing to chat to others struggling with sobriety.

Dr. Harry Haroutunian, who overcame his own addiction issues to become a leading physician at the Betty Ford Clinic, reveals he has often called on his rock star friend to help others.

He says, "Steven has on more than one occasion picked up the telephone. We've called him and put another patient on the line who was ready to go over the wall and leave treatment early and Steven's talked them back."

And Tyler himself admits he's always happy to help someone in trouble: "There's help... If you've got a problem, I know a place to go, I know some people to talk to and I'll talk to anybody. People say, 'Really, you'll give me your number?' And I'll say, 'Yeah, take my number'.

"If your grandson or a friend of yours (has problems) I'll call his a** up in the middle of the night and I'll say, 'Dude, what are you doing right now and where are you?'"