Former New York City Mayor Rudy Giuliani is joining President Donald Trump’s personal legal team to help with Special Counsel Bob Mueller’s probe into potential Russian meddling in the 2016 election, The Washington Post reported and The Daily Beast has confirmed.

Though talks had been ongoing, a formal announcement was delayed by a slew of foreign policy matters that took over much of the president’s time and agenda. A source familiar with the arrangement said that Trump had been preoccupied by North Korea and Syria, which limited his availability to speak with potential new members of his legal team.

Giuliani told the Post that he was joining the team “because I hope we can negotiate an end to this for the good of the country and because I have high regard for the president and for Bob Mueller.” He had not responded to The Daily Beast’s request for comment.

Trump has had notable difficulties in recruiting new lawyers. And in the former New York City Mayor, he has brought on board a close ally with strong roots in the legal world.

Giuliani served as the United States Attorney for the Southern District of New York during the 1980s. But his past several decades have been spent predominantly in politics. During the 2016 election, Giuliani campaigned with Trump and gave an impassioned speech in favor of Trump at the Republican National Convention in Cleveland.

“What I did for New York City, Donald Trump will do for America,” he said at the convention. “I have known Donald Trump for almost 30 years. And he has created and accomplished great things. But beyond that this is a man with a big heart. Every time New York City suffered a tragedy, Donald Trump was there to help.”

After Trump’s victory, however, Giuliani wasn’t selected for any cabinet post, leaving him on the outside of an administration he’d helped elect. Axios reported last summer that Trump had considered replacing Attorney General Jeff Sessions with Giuliani. But that too never happened.

The former mayor has largely stayed out of public view since then and has said little, if anything, about the Mueller-led investigation.

Giuliani previously represented Reza Zarrab, a Turkish businessman charged with participating in a scheme to evade American sanctions on Iran. Zarrab testified in federal court last November that two of his lawyers––presumably Giuliani and Michael Mukasey––tried to negotiate his release through a prisoner swap with Turkey. A federal judge called one of Giuliani’s affidavits about Zarrab’s alleged crimes “surprisingly disingenuous.”

Giuliani is not the only Trump campaign alum with Turkey ties. Former national security advisor Michael Flynn, who pleaded guilty to lying to the FBI, also cultivated close links with the country.  

This story has been updated