(CN) – Former New York Mayor Rudy Giuliani is joining President Donald Trump’s private legal team representing him in the Russia investigation.

Giuliani, a longtime Trump supporter, told The Washington Post in an interview that he is being brought on board to negotiate an end to the probe headed by Special Counsel Robert Mueller.

“I hope we can negotiate an end of this for the good of the country and because I have high regard for the president and for Bob Mueller,” Giuliani said.

Jay Sekulow, one of Trump’s personal attorneys, confirmed the hire in a written statement that said in part, “The President said, ‘Rudy is great. He has been my friend for a long time and wants to get this matter quickly resolved for the good of the country.”

Giuliani, who is chair of Greenberg Trauig’s Cybersecurity, Privacy and Crisis Management Practice, said he finalized his decision in recent days, and spoke with Trump about it last week at the president’s Mar-a-Lago resort in Palm Beach, Florida.

He also said he and the president spoke Thursday to discuss legal strategy going forward.

Giuliani will reportedly step down from his role at Greenberg Traurig, where he is also a senior advisor to the law firm’s executive chairman, to join the Trump legal team alongside Sekulow and Ty Cobb.

Sekulow also announced the addition of two other lawyers to the Trump legal team, Jane Serene Raskin and Marty Raskin. Both are former federal prosecutors.

“Jane and Marty are highly respected former federal prosecutors with decades of experience,” the statement said. “They have a nationwide practice and reputation for excellence and integrity.”

In March, John Dowd resigned as the president’s top outside attorney representing him in the investigation into Russian efforts to influence the 2016 election, reportedly because Trump repeatedly ignored his legal advice.

Before signing onto Trump’s legal team, Giuliani represented gold trader Reza Zarrab in a case involving billions of dollars laundered from Turkey to Iran. Giuliani negotiated with the Turkish government in that case in a failed attempt to find what he called a “diplomatic solution” to Zarrab’s prosecution.

Zarrab later pleaded guilty to violating U.S. sanctions against Iran and other charges when Giuliani’s efforts bore no fruit.

In 2014, Giuliani’s firm Greenberg Traurig registered as an agent for the Turkish government.

The course of the Russia investigation runs through Turkey via Trump’s disgraced General Michael Flynn, who pleaded guilty not only to misleading federal agents about his conversations with a Russian ambassador, but also omitting his ties to the Turkish government pursuant to the Foreign Agents Registration Act.

Courthouse News reporter Adam Klasfeld contributed to this report