(Reuters) - More than two months after Rudy Giuliani was sued by Dominion Voting Systems Corp for $1.3 billion over his claims that the company stole the election from Donald Trump, a lawyer has finally appeared in the case to defend him.

Giuliani turned to Joe Sibley of Camara & Sibley, an Austin, Texas-based litigator who is already representing the former New York mayor in a lawsuit filed by the NAACP over his alleged role in inciting the Jan. 6 riot at the U.S. Capitol.

On Wednesday Sibley made his appearance in the Dominion case and moved to dismiss it, arguing the company's Washington, D.C., federal court lawsuit is procedurally improper and vowing to fight if it proceeds.

Giuliani is also relying on Sibley in the $2.7 billion Smartmatic lawsuit pending against him in New York state court since February. Both Dominion and Smartmatic claim Giuliani defamed them through his assertions that they helped rig the 2020 U.S. presidential election in Joe Biden's favor.

Sibley is no stranger to defamation litigation. He is representing far-right activist Charles C. Johnson, who sued HuffPost last year after the news outlet described Johnson as a white supremacist and Holocaust denier.

Sibley is also representing Thomas Hubbard, a classics professor at the University of Texas professor who claims he was unfairly tarred as a pedophilia supporter by students at the school for his teachings on sexual relationships in Greek history. Hubbard has filed two federal lawsuits against students who have allegedly smeared him.

Hubbard said Sibley was recommended to him by an attorney acquaintance in New York. He said Sibley was charging him "a very reasonably flat rate" and that he is selective about the cases he takes on.

"Yes, Joe is very good, probably one of the top three plaintiff's libel specialists in Texas," Hubbard said in an email, adding, "He only takes libel cases he believes in."

According to his firm's website, Sibley is a former U.S. Army veteran, a graduate of both the University of Texas and Harvard Law School.

Apart from his defamation work, he also played a role in a landmark copyright infringement fight. He represented Jammie Thomas-Rasset, who was one of 18,000 individuals sued by the Recording Industry Association of America between 2003 and 2008 for illegally downloading music.

Thomas-Rasset fought the RIAA's claims, leading to three adverse jury verdicts that ranged from $54,000 and $1.92 million. The 8th U.S. Circuit Court of Appeals in St. Paul, Minnesota, held in 2012 that Thomas-Rassett had to pay $222,000 in damages.

The Thomas-Rasset case was the first file-sharing suit to reach a jury verdict, according to the Electronic Frontier Foundation. Sibley worked on the case alongside his then-partner Kiwi Camara, the other co-founder of Camara & Sibley. Camara left the firm in 2013 to found the e-discovery company known as DISCO.

Sibley's motion to dismiss the Dominion lawsuit on Wednesday argued that the company lacks jurisdiction and that it cannot adequately justify its request for money damages.

Sibley's filing said Giuliani denies defaming Dominion, adding that he "will provide a vigorous and complete response" if the case moves forward.

Sibley did not respond to a request for comment.

The case is US Dominion Inc et al v. Giuliani, U.S. District Court for the District of Columbia, 1:21-cv-00213.