WASHINGTON (Reuters) - Republican U.S. House of Representatives Speaker Mike Johnson will join former President Donald Trump at his hush money trial in Manhattan on Tuesday, a person familiar with the matter said.

Johnson, the top Republican in Congress, is the latest and most senior party member to attend the proceedings, in which Trump is charged with trying to cover up a payment to an adult film star in the final weeks of his 2016 presidential campaign.

North Dakota Governor Doug Burgum, widely seen as a possible Trump running mate, is also due to attend on Tuesday, along with hardline House Republicans Byron Donalds and Cory Mills and former Republican presidential candidate Vivek Ramaswamay.

Trump has already drawn support in the form of personal appearance from several Republicans on Capitol Hill including Republican Senators Rick Scott, J.D. Vance - another potential Trump vice president - and Tommy Tuberville.

On Monday, Vance, Tuberville and House Republican Nicole Malliotakis stood behind Trump in a courthouse hallway as he railed against the proceedings, the judge and his November rival, Democratic President Joe Biden.

Outside the courtroom, the lawmakers echoed Trump's theme that the prosecution is politically motivated and have attacked the credibility of Trump's former lawyer Michael Cohen, a star witness in the case.

(Reporting by David Morgan; additional reporting by Nathan Layne and Doina Chiacu; Editing by Scott Malone, Alexandra Hudson)