Aaron Carter made Robert Downey Jr. his rehab mentor

Pop star Aaron Carter chose recovering drug addict Robert Downey Jr. to be his mentor while seeking treatment at a rehab facility for a substance abuse issue.

Nick Carter's 28-year-old brother had an unhealthy addiction to anti-anxiety drug Xanax, and enrolled in a month-long program at the Betty Ford Clinic in California in 2011.

The facility has provided treatment to many celebrities including movie star Robert, whose highly-publicized drug issues and legal troubles led to a three-month stay at the clinic in 1998.

Since becoming sober, Robert has become one of the most successful and beloved movie stars in Hollywood, and Aaron admits he was hoping to follow his comeback once he completed rehab.

In an interview with Entertainment Tonight he says, "I probably shouldn't even say this, but I stayed in the same room that Robert Downey Jr. stayed in, and he became my idol because of Iron Man and what he did with his career. Then I made him my mentor without him even knowing about it."

Aaron reveals the Avengers star even left an inspirational message on a cork board for all patients at the facility, which reads: "I am here with you all."

The singer, who also admitted he still drinks wine and smokes marijuana to deal with his anxiety, hopes the next phase in his life will see him move onto bigger and better things.

"Everything makes me want to prove something," Aaron says. "Every obstacle that I'm put through, I'm turning into a positive."