(Reuters) - A federal appeals court revived a defamation lawsuit on Thursday against rocker Sammy Hagar, former lead singer for Van Halen, by a one-time Playboy bunny who claimed he fathered her son.

The 8th U.S. Circuit Court of Appeals said a lower court judge erred in dismissing claims by the woman after Hagar, 66, accused her in his 2011 autobiography "Red: My Uncensored Life in Rock" of extortion by naming him as the father.

Identified as "Jane Doe" in court papers, the woman claimed she had an intermittent five-year affair with Hagar in the 1980s, and became pregnant with his son after a June 1988 Van Halen concert in Detroit. She lived in Lansing, Michigan, at the time and later moved to Waterloo, Iowa.

Writing for a three-judge appeals court panel, Circuit Judge Myron Bright said the woman could pursue claims of libel, invasion of privacy and breach of a confidentiality agreement.

"Under Iowa law, an accusation that a person is a liar is defamatory as a matter of law," Bright wrote. "Indeed, Hagar's statements regarding Doe's criminality, dishonesty, and sexual exploits have a natural tendency to provoke Doe to wrath or expose her to public hatred, contempt, or ridicule within the community of individuals that recognize her as the subject."

The 8th Circuit upheld the dismissal of a claim alleging intentional infliction of emotional distress.

Wesley Kinnear, a lawyer for Hagar, said he had yet to discuss the decision with his client.

"We are disappointed that the Court of Appeals didn't affirm the lower court decision in its entirety," he said. "We look forward to the next step."

David Brown, a lawyer for Doe, said his client is "excited that she'll have her day in court. We think ultimately that Jane Doe will be fully vindicated, and that Mr. Hagar will be held fully accountable."

In his memoir, Hagar denied being the father, but said he agreed to pay the woman money during her pregnancy in exchange for her silence about his alleged paternity because his manager thought it was "the smart thing" to do.

The woman said she received $7,000 from Hagar.

Her son Dylan was born on Feb. 27, 1989, and died five days later. Hagar wrote he did not hear from the woman after the boy's death. No paternity tests were conducted.

"Obviously, it wasn't my baby, and they knew it," he wrote. "They just extorted me as long as they could."

The 8th Circuit returned the case to Chief Judge Linda Reade of the U.S. District Court in Cedar Rapids, Iowa.