Former New York Mayor Rudy Giuliani announced his decision to join President Donald Trump’s legal team as the Russia investigation by Special Counsel Robert Mueller continues.

“I’m doing it 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,” Giuliani said in an interview with the Washington Post.

Counsel to the President Jay Sekulow confirmed the news in a statement to reporters.

“I have had the privilege of working with Mayor Giuliani for many years, and we welcome his expertise,” he said.

The former New York City mayor, who was a key Trump supporter during the 2016 election, will leave his law firm Greenberg Traurig to join the president’s legal team.

“Rudy is great,” Trump said in the statement. “He has been my friend for a long time and wants to get this matter quickly resolved for the good of the country.”

Giuliani was a rumored candidate to serve as Trump’s attorney general, but the job went to Sen. Jeff Sessions instead, who recused himself from the ongoing Russia investigation.

Giuliani had a long legal career before he was elected mayor of New York City in 1997. After an unsuccessful run for Senate and failing to win the Republican nomination for president in 2008, he returned to the private sector.

Sekulow announced that Jane Serene Raskin and Marty Raskin had also joined Trump’s legal team, citing their “reputation for excellence and integrity.”