It's an all-too familiar situation for Iron Man star Robert Downey Jr. He knows what it's been like to struggle with a drug problem.

Now it's his son who is battling with drugs. According to People, Downey Jr's son, Indio, has had his bouts with substance abuse issues for a couple of years now. The 20-year-old voluntarily checked himself into rehab after he was arrested for cocaine possession

Robert Downey Jr. is intent on helping his son emerge victorious from his battle with substance abuse.

"Robert clearly understands the struggle, and while of course this relapse was very upsetting to him, he is very proud of his son," says an insider who spoke with People magazine.

The Iron Man star will be able to draw from the lessons that he learned from his journey towards sobriety in guiding his son.

It will be recalled that reports about the actor's drug use eclipsed his talent as an actor, after several charges related to possession and use of marijuana, cocaine and heroin were filed against him.

The actor was subsequently dropped by TV and movie projects after his arrest, erratic behavior, and continued drug usage. But the actor was able to turn his life back around by going to rehab. It will be remembered that it was Mel Gibson's 2003 movie The Singing Detective that marked the actor's comeback. Since then, he has been sober, and has redeemed himself with his successful movies, such as the Iron Man franchise and the Avengers series.

Downey Jr.'s ex-wife, Deborah Falconer, who is Indio's mother is also supportive of her son's sobriety efforts. The source of People magazine share that the young man is intent on staying out of drugs. "Indio truly wants to stay clean," the source says. "And no matter what, his dad will be right there with him."

Even with this current issue in the family, Robert Downey Jr. has reason to celebrate. He recently announced that he and his wife Susan are expecting a baby girl due in November.