Longtime Senate GOP Leader Mitch McConnell, R-Ky., says he'll be in attendance on Thursday as Senate Republicans meet in the nation's capital with former President Donald Trump. It will be the first time Trump and McConnell will have seen each other in person in nearly four years. Trump, the GOP's presumptive presidential nominee, is holding behind closed doors meetings Thursday morning with House Republicans and Thursday afternoon with Senate Republicans. And McConnell reiterated to reporters on Wednesday that "I'll be at the meeting tomorrow." TRUMP'S IMMENSE GRIP OVER GOP REMAINS FIRM AS HIS ENDORSED CANDIDATES RUN THE TABLE IN REPUBLICAN PRIMARIES McConnell and Trump haven't talked since December 2020, as their working relationship turned frosty following President Biden's election victory over then-President Trump. McConnell formally recognized Biden's presidential election victory after the former vice president was confirmed the winner by the Electoral College on Dec. 15, 2020. A few weeks later, McConnell said Trump was "morally responsible" for the Jan. 6, 2021, attack on the U.S. Capitol by Trump supporters who aimed to upend congressional certification of Biden's White House win. Trump, in the ensuing years, regularly lambasted McConnell in social media posts, calling him, among other things, an "absolute loser." And the former president also made derogatory remarks about McConnell's wife, Elaine Chao, who served as Trump's transportation secretary. But fast-forward to this year and McConnell endorsed Trump after the former president in early March clinched the 2024 GOP nomination. "It is abundantly clear that former President Trump has earned the requisite support of Republican voters to be our nominee for President of the United States," McConnell said at the time. "It should come as no surprise that as nominee, he will have my support." On Wednesday, McConnell emphasized during his weekly Senate leadership news conference that "I said three years ago, right after the Capitol was attacked, I would support our nominee regardless of who it was, including him. I've said earlier this year, I support him. He's earned the nomination by the voters all across the country." Get the latest updates from the 2024 campaign trail, exclusive interviews and more at our Fox News Digital election hub.