Donald Trump will host a group of nearly two dozen influential Republicans on Monday afternoon for an off-the-record gathering that his allies hope will improve his relationship with the congressional GOP and the party's Washington establishment, according to two people who were invited.

The meeting is Trump's first major meeting with lawmakers and key Republican figures since last fall, when he met with a smaller group at the Capitol after his speech at a protest against the Iranian nuclear agreement.

Several members of the House and Senate are expected to participate, plus a bevy of consultants and veteran power brokers, the people said, requesting anonymity to discuss the session.

U.S. Senator Jeff Sessions speaks next to U.S. Republican presidential candidate Donald Trump supporters at a rally at Madison City Schools Stadium in Madison, Alabama February 28, 2016. REUTERS/Marvin Gentry Sen. Jeff Sessions speaks to Donald Trump supporters at a rally last month in Madison, Ala. (Marvin Gentry/Reuters)

Sen. Jeff Sessions (R-Ala.), the populist-right favorite who endorsed Trump last month, and Trump campaign counsel Donald F. McGahn organized the meeting along with Trump's advisers. The venue will be McGahn's law firm, Jones Day, which is a short walk from the Capitol.

When asked Saturday about the meeting, Trump campaign manager Corey Lewandowski confirmed that the candidate would meet privately with Republicans ahead of his speech Monday to the American Israel Public Affairs Committee's policy conference in Washington. He declined to provide a list of attendees.

"Mr. Trump is continuing his outreach to Washington and there has been an overwhelming positive response," Lewandowski said in a brief phone interview.

The people invited to attend both said they were told that the meeting would be focused on "party unity" and intended to help Trump get to know more elected leaders and other players, including some Republicans who have not endorsed the billionaire mogul.