New. York CNN  —  Teamsters President Sean O’Brien will speak to the Republican National Convention in Milwaukee in July, a sign that former President Donald Trump’s campaign is hoping to peel off the support of union members from President Joe Biden. But unlike other speakers at the RNC, O’Brien’s appearance does not represent an endorsement of Trump, according to Teamsters union spokesperson Kara Deniz. O’Brien has requested the opportunity to also speak at the Democratic National Convention in Chicago in August. The DNC has yet to accept that request, Deniz said. Trump posted the announcement Friday afternoon on his Truth Social platform. “Our GREAT convention will unify Americans and demonstrate to the nation’s working families they come first,” Trump wrote. “When I am back in the White House, the hardworking Teamsters, and all working Americans, will once again have a country they can afford to live in and be respected around the world. Sean, I look forward to seeing you represent the Teamsters in Milwaukee. Together we can Make America Great Again.” Deniz said in an email that the union was happy Trump extended the invitation. “This is truly unprecedented since it will be the very first time a Teamsters General President has addressed the RNC,” she said in an email. “Our 1.3 million members represent every political background, and their message needs to be heard by as wide an audience as possible, and that includes all political candidates running for elected office. We appreciate former President Trump’s openness to inviting a labor leader to speak on behalf of working families.” “We sincerely hope the DNC will also respond to our request with an invitation,” she said. Trump and O’Brien met at the former president’s Mar-a-Lago resort in early January. Trump then met with the union’s leadership on January 31. Some other union leaders objected to the meetings, with John Palmer — the group’s international vice president at-large — writing a letter at that time denouncing Trump as “a known union buster, scab, and insurrectionist.” “We should never entertain dialogue with a candidate with such an anti-union record,” he wrote. Biden has a very pro-union record. He became the first sitting president to appear on the picket line to support strikers during the United Auto Workers union’s strike against the nation’s three unionized automakers. He has regularly voiced support for unions and has appointed a very pro-union leadership to the National Labor Relations Board, which has been much friendlier to union positions during his administration. He also met with the Teamsters leadership in March. But so far, the Teamsters have endorsed neither candidate, unlike the AFL-CIO and many powerful unions, such as the UAW and the National Education Association. And the union’s political arm gave similar size donations of hundreds of thousands of dollars to committees of both the Democratic and Republican parties earlier this year. O’Brien has had his own harsh criticism of some other Republicans, if not Trump. At a Senate hearing in November, he and Sen. Markwayne Mullin, a Republican from Oklahoma, both said they were prepared to engage in a fist fight in the middle of a hearing until Sen. Bernie Sanders, the committee chair, ordered them to stop. The DNC said it has yet to settle on its set of speakers for its convention in August. “We are building a convention in Chicago that will tell our story to the American people, including the stories of labor and union leaders and workers that President Biden has been delivering for as the most pro-union president in modern history,” said DNC spokesperson Matt Hill.