Alan Dershowitz, a constitutional lawyer, and Robert Ray, Starr's successor to the Independent Council Office during the Clinton administration, are also joining the team, people said.
The three are expected to join a legal team led by White House attorney Pat Cipollone and external lawyer Jay Sekulow, who is yet to deliver statements on behalf of the president in the Senate plenary. Former Florida Attorney General Pam Bondi and longtime Trump's personal lawyer Jane Raskin will also complement the president's impeachment legal team, a person familiar with the matter said.
A spokesman for Trump's legal team said Dershowitz will make oral arguments in the Senate trial.
"He is participating in this impeachment trial to uphold the integrity of the constitution and prevent the creation of a dangerous constitutional precedent," said the legal team, which observed Dershowitz against Clinton's impeachment and voted for his wife, Hillary Clinton, in the 2016 election. presidential.
Starr and Ray must play a constitutional and historical role during the proceedings to support Cipollone and Sekulow.
Bondi works at the White House as a consultant during the impeachment process. Raskin is a white-collar defense lawyer who, along with her husband, worked for Trump during Mueller's investigation.
The decision to allow Republican allies to participate in the defense is still fluid, people with the matter said.
Authorities are hesitant to talk about who they are adding to the legal team following a failed attempt to hire Trey Gowdy last fall. Gowdy became the new face of Trump's impeachment defense team for just a matter of hours before Trump said federal lobbying rules would not allow him to begin until January. He continued to talk to Gowdy privately about the situation.
This story has been updated to include additional reports and background.