Washington (CNN) President Donald Trump is adding three seasoned lawyers to his impeachment legal defense team , the White House confirmed Friday night, including Kenneth Starr, the hard-charging prosecutor whose work led to President Bill Clinton's impeachment.

Alan Dershowitz, the constitutional lawyer, and Robert Ray, Starr's successor at the Office of Independent Counsel during the Clinton administration, are also joining the team, White House press secretary Stephanie Grisham said in a statement.

The three are expected to join a legal team headed by White House counsel Pat Cipollone and outside attorney Jay Sekulow, who are still expected to deliver statements on the President's behalf on the Senate floor. Former Florida Attorney General Pam Bondi, Trump's longtime personal counsel Jane Raskin and attorney Eric Herschmann will also supplement the President's impeachment legal team, Grisham said. All are expected to have speaking roles, people familiar with the matter told CNN.

"President Trump has done nothing wrong and is confident that this team will defend him, the voters, and our democracy from this baseless, illegitimate impeachment," Grisham said in the statement.

Trump's impeachment trial over the Ukraine scandal officially began on Thursday . The outcome is all but determined, as the two-thirds vote required to remove the President would need 20 Republican senators to break rank. The White House did not mount a formal defense during the House's investigation as it refused to cooperate with the Democratic-led probe

A spokesman for Trump's legal team said Dershowitz will present oral arguments at the Senate trial.

"He is participating in this impeachment trial to defend the integrity of the Constitution and to prevent the creation of a dangerous constitutional precedent," said the legal team, which noted Dershowitz opposed Clinton's impeachment and voted for his wife, Hillary Clinton, in the 2016 presidential election.

Later Friday, Dershowitz t old the website Mediaite it was an exaggeration to say he was joining the team per se. Instead, he described his role as more confined.

"I think it overstates it to say I'm a member of the Trump team. I was asked to present the constitutional argument that I would have presented had Hillary Clinton been elected and had she been impeached," Dershowitz told the website. "I was asked to present my constitutional argument against impeachment. I will be there for one hour, basically, presenting my argument."

In an interview with CNN's Anderson Cooper on "Anderson Cooper 360," Dershowitz was asked to clarify his role as part of the legal team appearing at the Senate trial on behalf of Trump. He said he has been asked to "prepare and deliver the constitutional case against impeachment that benefits the President."

"It's the same argument I would have made if Hillary Clinton had been elected and had been impeached," Dershowitz said. "I will go into the history of the formulation in the Constitution and the history of how these words came to be and leave it to others to argue the facts, to make strategic decisions about witnesses. That's not within my jurisdiction."

Dershowitz referred to himself as an "advocate against impeachment."

Starr, Dershowitz and Ray are expected to play a constitutional and historic role during the proceedings to support Cipollone and Sekulow.

Trump has relied on Dershowitz for advice throughout the Mueller investigation and during his impeachment. The two had been in discussions about Dershowitz joining for several weeks.

Bondi has been working at the White House as an adviser during the impeachment proceedings. Raskin is a white-collar defense lawyer who, along with her husband, worked for Trump during the Mueller investigation.

A decision on allowing House GOP allies to participate in the defense is still fluid, people with the matter said.

Officials have been hesitant to speak about who they are adding to the legal team after a botched attempt to hire Trey Gowdy last fall. Gowdy became the new face of Trump's impeachment defense team for only a matter of hours before Trump said federal lobbying rules wouldn't allow him to begin until January . He has continued to speak to Gowdy privately about the situation.

Celebrity defense attorneys

Trump's decision to add Starr, Dershowitz and Ray not only adds decades of experience to his defense but legal star power for a President always mindful of having advocates who can present his case well in the media.

Dershowitz, a Harvard Law School professor, gained fame as a member of O.J. Simpson's defense team in the ex-football star's criminal trial in the mid-1990s. He's since defended many notable clients and remains a familiar legal analyst on television. Some aides have privately voiced concerns that his presence could be distracting given his ties to Jeffrey Epstein, the late pedophile businessman. Dershowitz is embroiled in a lawsuit with a woman who claims she was a victim of Epstein's, who also claims Dershowitz sexually abused and defamed her. Dershowitz has since countersued, claiming she defamed and intentionally inflicted emotional distress on him.

Starr became a household name in the late 1990s as the then-independent counsel overseeing the investigation that led to Clinton's impeachment. The probe began with Starr looking into the Clintons' involvement with the Whitewater land deal before the investigation expanded to include the extramarital affair between Bill Clinton and former White House intern Monica Lewinsky.

When Starr stepped down in October 1999 , citing the "intense politicization of the independent counsel process," he was succeeded by Ray.

After the announcement Friday morning, Lewinsky tweeted, "this is definitely an 'are you f---ing kidding me?' kinda day."

This story has been updated to include additional reporting and background.