Cameron Douglas writes letter to judge as he awaits sentencing

Michael Douglas' incarcerated son, Cameron, has written a letter to a judge, expressing his "shame and penitence" ahead of his sentencing for a new drug possession charge.

RELATED: Year in Review: Trouble With the Law 2011

Cameron Douglas is currently serving a five-year prison sentence after being convicted of methamphetamine possession with intent to distribute, and one count of cocaine possession, stemming from an arrest two years ago.

The 33-year-old faces an additional 18 months behind bars after authorities found what appeared to be heroin and cocaine in his cell.

RELATED: Remorse Code: Memorable Celebrity Apologies

In October, Cameron admitted to smuggling narcotics into prison, telling the court, "God knows I'm sorry about this situation."

The letter to the judge begs for "the opportunity to build myself and gain the tools I need to shape my future," ahead of his sentencing on Wednesday.

In the court filing, obtained by the New York Post, he adds, "I feel so strongly, for the first time in my life, that I am truly ripe for positive reform and real achievement," adding that he's "been battling this disease of addiction, as you know, for more than half of my life."

RELATED: Celebrity Offspring