Levi Johnston's mom pleaded guilty to one count of possession with intent to deliver the prescription painkiller OxyContin on Wednesday, the Associated Press reports.

See the biggest celebrity scandals of 2008.

Sherry Johnston -- whose 19-year-old son is the father of former Alaska governor Sarah Palin's first grandchild -- is scheduled to be sentenced in November.

See photos of stars in court.

Although she could receive 20 years in jail, her attorney and prosecutors arranged a plea deal in which she will likely serve five years in prison with two years suspended. Levi Johnston -- who was engaged to Bristol Palin, 18, before she called off the wedding -- did not attend his mother's hearing. His younger sister, Mercede, attended. In mid-December, Sherry was charged with six felony counts of misconduct involving a controlled substance. (A short time later, Bristol gave birth to her and Levi's son, Tripp.)

See photos of more shocking teen pregnancies.

According to police reports, she received OxyContin pills in the mail, then sold 10 pills to a police informant on three occasions in October and November of last year. The meet-ups were arranged by cell phone text messages and conducted in Wasilla parking lots.

Get more Us! Follow us on Twitter, Friend us on Facebook, Subscribe to Us Weekly