NEW YORK (Reuters) - Former New York Mayor Rudy Giuliani, a one-time federal prosecutor, is joining U.S. President Donald Trump's personal legal team, Trump lawyer Jay Sekulow said in a statement on Thursday.
"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," Sekulow quoted Trump as saying.
Giuliani was one of three attorneys Sekulow said were being added to the president's legal team dealing with Special Counsel Robert Mueller's investigation into Russian interference in the 2016 election.
Russia has denied meddling in the election. Trump has said there was no collusion and has called the Mueller probe a "witch hunt."
The Republican mayor of New York from 1994 to 2001, Giuliani was also the chief federal prosecutor in Manhattan for much of the 1980s. During that time, he brought many high-profile cases targeting insider trading on Wall Street.
Rudy Giuliani through the years
Rudy Giuliani through the years
Rudy Giuliani, former mayor of New York, smiles while arriving to participate in a discussion during the Values Voter Summit with Donald Trump, 2016 Republican presidential nominee, not pictured, in Washington, D.C., U.S., on Friday, Sept. 9, 2016. Trump and his running mate said this week that Russian President Vladimir Putin is a stronger leader than U.S. President Barack Obama, provoking Democratic condemnation and prompting some Republicans to distance themselves. Photographer: Andrew Harrer/Bloomberg via Getty Images
NEW YORK, NY - FEBRUARY 27: Rudolph Giuliani, US Attorney for the Southern District of New York, is photographed February 27, 1985 announcing the arrests in the 'Commission' case. A Federal racketeering indictment charged nine men with participating in a ''commission'' that governs the five organized-crime ''families'' in New York City. (Photo by Yvonne Hemsey/Getty Images)
D.A. Rudolph Giuliani at Daily News Newsmakers Conference. (Photo By: Anthony Casale/NY Daily News via Getty Images)
Koch & Giuliani, join comm. of Doi Kevin Frawley, outline the guilty pleas of six arrested in bribes. 1. Giuliani and Koch await their turn in press con at D.O.I. 80 Maiden Lane. 2. Giuliani and Koch. 3. Head to Head after Giuliani gave Koch an Excellent to a reporter's questionKoch got up to shake his hand when he was through. January 17, 1989. (Photo by Louis Liotta/New York Post Archives / (c) NYP Holdings, Inc. via Getty Images)
Giuliani holds press conference about the NYC homeless. August 01, 1989. (Photo by Dan Brinzac/New York Post Archives / (c) NYP Holdings, Inc. via Getty Images)
Guiliani at Inside Edition -- New TV personality at Inside Edition, Rudy Guiliani. Rudy Guiliani. Rudy honing up before taping of his part of the show. Rudy reviewing tapes in editing room. March 12, 1990. (Photo by Michael Schwartz/New York Post Archives / (c) NYP Holdings, Inc. via Getty Images)
Rudy Giuliani. November 05, 1993. (Photo by David Rentas/New York Post Archives / (c) NYP Holdings, Inc. via Getty Images)
UNITED STATES - JANUARY 02: Andrew Giuliani yawns as his father Rudy speaks after he was sworn in as mayor of New York City. (Photo by Budd Williams/NY Daily News Archive via Getty Images)
Rudy Giuliani. January 12, 1994. (Photo by David Rentas/New York Post Archives / (c) NYP Holdings, Inc. via Getty Images)
Police, criminal justice unions endorse Cuomo for governor on steps of City Hall. Thomas Scotto, Pres. of N.Y.C.P. detectives, endorsement assoc. was between them. October 25, 1994. (Photo by Michael Norcia/New York Post Archives / (c) NYP Holdings, Inc. via Getty Images)
(Original Caption) California governor Pete Wilson meets with New York City mayor Rudy Giuliani at city hall. (Photo by mark peterson/Corbis via Getty Images)
UNITED STATES - SEPTEMBER 26: New York Knicks' President David Checketts (left) and NBA Commissioner David Stern present Mayor Rudy Giuliani with a Giuliani 98 jersey. The 1998 NBA All-Star game will be held in New York City. (Photo by Keith Torrie/NY Daily News Archive via Getty Images)
UNITED STATES - JULY 02: Shadow of Mayor Rudy Giuliani shows against background after he was endorsed by the hotel workers union at the Waldorf-Astoria., (Photo by Susan Watts/NY Daily News Archive via Getty Images)
26 Oct 1996: New York City mayor Rudy Guilliani, George Steinbrenner, and New York Yankees manager Joe Torre celebrate after Game Six of the World Series against the Atlanta Braves at Yankee Stadium in New York City, New York. The Yankees won the game, 3-
UNITED STATES - MAY 04: Mayor Rudy Giuliani is flanked by CBS President Leslie Moonves (left) and Donald Trump at news conference at the GM Building, where CBS announced that Bryant Gumbel will be the host of its new morning news program, 'This Morning.' Show, to be launched Nov. 1, will broadcast from Trump's International Plaza Building., (Photo by Andrew Savulich/NY Daily News Archive via Getty Images)
399759 01: Former New York Mayor Rudy Giuliani made his first appearance on 'The Tonight Show with Jay Leno' January 16, 2002 in Burbank CA. Giulani talked about the events of September 11 and his recent selection as Time Magazine's 'Man of the Year.' (Photo by Paul Drinkwater/NBC via Getty Images)
SATURDAY NIGHT LIVE -- Episode 9 -- Air Date 12/15/2001 -- Pictured: (l-r) Tina Fey, Rudy Giuliani, Jimmy Fallon during 'Weekend Update' on December 15, 2001 (Photo by Dana Edelson/NBC/NBCU Photo Bank via Getty Images)
400517 05: Former New York City Mayor, Rudy Giuliani, gives a thumbs up to football fans before Super Bowl XXXVI February 3, 2002 in New Orleans, LA. Super Bowl XXXVI will be played by the New England Patriots and the St. Louis Rams at the Superdome in New Orleans, LA. (Photo by Jed Jacobsohn/Getty Images)
MANCHESTER, UNITED KINGDOM - JANUARY 22: Former New York Mayor Rudolph Giuliani smiles as he sits with copies of his book 'Leadership', published last October on January 22, 2003 in Waterstones bookshop, Deansgate, Manchester, England. The book outlines 'the principles Giuliani has worked through, and how he has adhered to them through his career, and how they came into play in the aftermath of the World Trade Centre'. (Photo by Gary M.Prior/Getty Images)
CEDAR RAPIDS, IA - JANUARY 19: Former New York City Mayor Rudy Giuliani gestures as he takes questions from emergency personnel at a rally held to drum up support for the 2004 Bush-Cheney presidential ticket January 19, 2004 in Cedar Rapids, Iowa. Iowa will be the first state in the nation to test the popularity of the Democratic presidential hopefuls when it holds the caucuses tonight. (Photo by Scott Olson/Getty Images)
UNITED STATES - DECEMBER 24: Former Mayor Rudy Giuliani kisses the hand of a little girl as he visits Hale House in Harlem on the day before Christmas to pass out gifts and read holiday stories to the children. (Photo by Susan Watts/NY Daily News Archive via Getty Images)
NEW YORK - SEPTEMBER 11: Former New York City Mayor Rudolph Giuliani speaks as he makes a tribute to the victims of the terrorist attacks of 2001 on September 11, 2005 in New York City. This is the fourth anniversary of the September 11th attacks. (Photo by Daniel Berehulak/Getty Images)
WILKES-BARRE, PA - NOVEMBER 3: Former New York City Mayor Rudy Giuliani (R) speaks as U.S. Sen. Rick Santorum (R-PA) (L) looks on at a campaign rally November 3, 2006 in Wilkes-Barre, Pennsylvania. Santorum faces Democratic challenger Bob Casey Jr. in the November election. (Photo by Jeff Fusco/Getty Images)
SPARTANBURG, SC - FEBRUARY 21: Republican presidential hopeful, former New York Mayor Rudy Giuliani holds a campaign rally with first responders at the North Spartanburg Fire Department on February 21, 2007 in Spartanburg, South Carolina. (Photo by Charles Ommanney/Getty Images)
HENDERSON, NV - NOVEMBER 01: Former New York City Mayor Rudy Giuliani reacts as he is greeted by supporters at a McCain-Palin regional headquarters office November 1, 2008 in Henderson, Nevada. As candidates continue to bring out the political heavy-hitters for their last pitches, Giuliani will be campaigning in several states for Republican presidential nominee Sen. John McCain (R-AZ) leading up to the election on November 4. (Photo by Ethan Miller/Getty Images)
NEW YORK - NOVEMBER 06: Former New York City Mayor Rudy Giuliani celebrates during the New York Yankees World Series Victory Parade on November 6, 2009 in New York, New York. (Photo by Jared Wickerham/Getty Images)
LATE NIGHT WITH JIMMY FALLON -- Episode 487 -- Pictured: (l-r) Former New York City Mayor Rudy Giuliani during an interview with Jimmy Fallon on August 8, 2011 (Photo by Lloyd Bishop/NBC/NBCU Photo Bank via Getty Images)
UNITED STATES â SEPTEMBER 6: Former New York mayor Rudy Giuliani waits to speak at the National Press Club luncheon in Washington on Tuesday, Sept. 6, 2011. (Photo By Bill Clark/Roll Call)
July 27, 2012 Former NYC Mayor Rudy Giuliani and the Republican Team Meet & Greet to Support Romney in his Presidential Campaign. Mayor Giuliani looking for support as the guest speaker in the Cuban Community of Calle Ocho - Little Havana in South FloridaFlorida (Photo by Michele Eve Sandberg/Corbis via Getty Images)
SCARBOROUGH, NY - JULY 17: Rudy Giuliani attends Joe Torre Safe At Home Foundation 2013 Golf and Tennis Classic at Sleepy Hollow Country Club on July 17, 2013 in Scarborough, New York. (Photo by Bobby Bank/Getty Images)
Florida Gov. Rick Scott and former Mayor of New York Rudy Giuliani, arrive at a campaign stop in Miami, as Scott kicks off the Get Out the Early Vote bus tour (Photo by Michele Eve Sandberg/Corbis via Getty Images)
NEW YORK, NY - APRIL 15: Former Mayor of New York City Rudy Giuliani attends the Opening Night premiere of 'Live From New York!' during the 2015 Tribeca Film Festival at the Beacon Theatre on April 15, 2015 in New York City. (Photo by Jamie McCarthy/Getty Images for the 2015 Tribeca Film Festival)
PHOENIX, AZ - AUGUST 31: Rudy Giuliani, former mayor of New York City, speaks in support of Republican presidential candidate Donald Trump during a Trump campaign rally on August 31, 2016 in Phoenix, Arizona. (Photo by Ralph Freso/Getty Images)
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Giuliani was also a top Department of Justice official in the Reagan administration.
Since exiting the mayor's office, Giuliani has been in private practice, most recently at the law firm of Greenberg Traurig. The firm said Giuliani is on a leave of absence, effective today.
Sekulow also announced two other lawyers were joining Trump's legal team, the south Florida husband-and-wife white-collar defense lawyers Martin and Jane Raskin.
(Reporting by Karen Freifeld; writing by Eric Beech; editing by Tim Ahmann and Lisa Shumaker)