A California doctor charged in the overdose death of Friends star Matthew Perry has agreed to plead guilty, according to a court filing.

Salvador Plasencia is expected to enter guilty pleas within weeks to four counts of illegal distribution of the drug ketamine, federal prosecutors said.

They said offences carry a maximum possible sentence of 40 years in prison.

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Plasencia and a woman accused of being a ketamine dealer had been the primary targets of the prosecution after three other defendants, including another doctor, agreed to plead guilty in exchange for their co-operation.

Plasencia had been scheduled to stand trial in August.

Perry died, at age 54, in October 2023 from acute effects of ketamine and other factors that caused him to lose consciousness and drown in his hot tub, according to a December 2023 autopsy report.

The US actor had publicly acknowledged decades of substance abuse, including during the years he starred as Chandler Bing on the hit 1990s TV sitcom Friends.

He starred alongside Jennifer Aniston, Courteney Cox, Lisa Kudrow, Matt LeBlanc and David Schwimmer for 10 seasons from 1994 to 2004.

— With AP