Renita Hill, 48, sued the former The Cosby Show star in October (15), claiming he and his lawyers made her appear as a "liar" after vehemently denying allegations he had drugged her drinks and molested her while she was passed out during their stint on the road together in the 1980s.

She went public with her story in a U.S. TV interview in 2014, joining a string of other reported victims, who had come forward with similar stories about time they spent with the veteran actor and comedian.

Cosby's lawyers blasted Hill's defamation case, insisting her claims held no merit as she had never been mentioned by name in the original statements of denial. They also argued that even if Hill was referred to in the press releases, the comments had been simply a matter of opinion and were therefore protected by constitutional law.

A federal judge in Pennsylvania sided with Cosby in January (16) and threw out Hill's case without prejudice, banning her from amending and re-filing in future.

However, her lawyer, George M. Kontos, is now challenging the ruling, filing papers at the 3rd U.S. Circuit Court of Appeals on Friday (22Apr16), reports The Associated Press.

In the court documents, he wrote, "All three statements are defamatory because they imply that Ms. Hill lied about being sexually assaulted."

Cosby is also facing another similar suit from seven women in Massachusetts, who also insist their reputations were damaged when their credibility was called into question after detailing their decades-old sex allegations against the 78-year-old.

Cosby's wife, Camille, sat for a deposition regarding that case on Tuesday (19Apr16), but remained silent and refused to revoke her marital privilege as she was questioned by one of the plaintiffs' lawyers, Joseph Cammarata.

The funnyman is also fighting criminal charges in Pennsylvania, relating to an alleged 2004 attack on Andrea Constand, an employee at his alma mater, Temple University. He is currently free on $1 million (£670,000) bail following his arrest in December (15), although his legal team is attempting to have the case dismissed, suggesting a previous prosecutor broke a promise not to press charges over the embattled comedian's encounter with Constand.