The District Attorney's Office said in a statement that it had declined to file sexual assault charges against Masterson in two other cases because of insufficient evidence and because of the statute of limitations.
Masterson, 44, got his break-out role in the 1998-2006 television comedy series "That 70s Show," in which he played a rebel adolescent. He could not immediately be reached for comment on the charges.
In a statement issued to Variety, Tom Mesereau, Masterson's attorney, vowed to fight the charges.
"Mr. Masterson is innocent, and we're confident that he will be exonerated when all the evidence finally comes to light and witnesses have the opportunity to testify," Mesereau said in the statement. "The people who know Mr. Masterson know his character and know the allegations to be false."
