Michael Douglas' troubled son Cameron has reportedly been released from solitary confinement six months after his movie star dad made an impassioned plea for leniency towards the 35 year old at the 2013 Emmy Awards.

Cameron was jailed in 2009 after being found guilty of conspiracy to distribute narcotics after he was caught selling heroin, and he was cut off from his family and other inmates in 2012 following a relapse behind bars.

Due for release in 2018, Douglas is now free to roam Maryland's Cumberland Federal Corrections Institute - and he will be able to receive visitors again, according to reports.

That will please his father, who revealed he was "questioning the system" in his Emmys speech.

The actor said, "At first I was certainly disappointed with my son, but I've reached a point now where I'm disappointed with the system. If you happen to have a slip, they punish you. In my son's case, he has spent almost two years in solitary confinement."