Ryan O'Neal pled guilty in a Malibu court Friday to possessing methamphetamines.
His son Redmond was in court facing the same charge, but had his case continued until February 20.
The actor was sentenced to 18 months in a drug rehabilitation program, after which, should he complete the program successfully, the charge will be removed from his criminal record.
O'Neal is also forbidden from possessing any controlled substance or associating with anyone whom he knows to be a drug user.
Not counting his son Redmond.
O'Neal, 67, was subdued in court, and said only the word "guilty" when asked for his plea.
O'Neal was arrested September 17 at his Malibu home when Los Angeles County Sheriff’s deputies found drugs in his bedroom during a search of the house related to son Redmond's probation.