Robert Downey Jr and his son Indio

Robert Downey Jr. has reportedly been trying to help his son with his drug addiction for “years”.

The 'Iron Man 3' star – who has famously battled with substance abuse in the past – has been providing counselling for his oldest son Indio, 20, as he feels he's partly to blame for the youngster's issues with drugs.

A source told “Because of Robert's own struggle he's very much in tune with his son's sobriety. And that has really helped Indio.”

Indio - whose mother is Robert's ex-wife Deborah Falconer - has reportedly been in and out of rehab for many years, but has managed to stay clean until recently.

He proved he had fallen off the straight and narrow on Sunday when he was arrested for possession of cocaine in West Hollywood after police caught him smoking something out of a pipe in a car.

Indio was booked for possession of cocaine, but was released from jail at midnight after posting $10,000 bail.

Robert, 49, released a statement today claiming his son “likely inherited” his weakness for substance abuse, but will hopefully overcome it.

He said: “Unfortunately there's a genetic component to addiction and Indio has likely inherited it. There is a lot of family support and understanding, and we're all determined to rally behind him and help him become the man he's capable of being.

“We're grateful to the Sheriff's department for their intervention, and believe Indio can be another recovery success story instead of a cautionary tale.” – Bang Showbiz