Former president Donald Trump found himself in a rare position on Sunday — getting booed by his own supporters after he told them he’d gotten a coronavirus vaccine booster.

Trump was in Dallas with conservative pundit Bill O’Reilly for the final stop of their two-man live interview show, “The History Tour,” when Trump started taking credit for his administration developing vaccines that have “saved tens of millions of lives worldwide.” He told the crowd to be proud of the coronavirus vaccines and said that bad-mouthing their effectiveness is “playing right into their hands,” an apparent reference to their shared political enemies.

At one point, O’Reilly stepped in: “Both the president and I are vaxxed and,” he said, turning to Trump, “did you get the booster?”

“Yes,” Trump replied.

“I got it, too,” O’Reilly added.

Then, some in the crowd booed them.

“Don’t, don’t, don’t, don’t,” Trump scolded them, waving his hand dismissively.

It was an unusual moment for Trump, who remains popular in the Republican Party. According to a Pew Research Center poll conducted in September, two-thirds of Republicans want him to remain a major force in American politics for years to come, and 44 percent want him to run for president in 2024.

That popularity, however, has not made him immune to occasional jeers from even the most die-hard supporters. In August, a crowd booed him at one of his hallmark rallies in Alabama. Again, the subject was vaccines.

O’Reilly told NewsNation Now’s Dan Abrams that Trump’s Sunday exchange with the crowd was good for the former president.

“This is good that people see another side of you,” O’Reilly said he told Trump in a phone call. “Not a political side. You told the truth — you believe in the vax.”

Federal research has found Trump’s views played a significant role in spreading misinformation and fomenting the response to vaccines he was fighting at Sunday’s event. While in office, he downplayed the seriousness of the coronavirus early in the pandemic, repeatedly saying it would just “go away,” even as infections and deaths swelled. He flouted his own administration’s safety protocols by holding large rallies and packing the White House with unmasked guests. He and former first lady Melania Trump got vaccinated in private before leaving office, while other top officials — including his own vice president — made a show of doing so publicly. In September, Trump told the Wall Street Journal he “probably” wouldn’t get a booster shot and, in August, suggested they were a “money-making operation” during an interview with Fox Business host Maria Bartiromo.

But he’s also periodically voiced support for vaccines, while also making it clear he rejects mandates requiring people to get them, something he did again on Sunday in Dallas.

“If you don’t want to take it, you shouldn’t be forced to take it — no mandates,” Trump said. “But take credit, because we saved tens of millions of lives.”

Trump was hospitalized with the coronavirus in October 2020. At least two people briefed on his medical condition told The Washington Post earlier this year that he was gravely ill and they were scared he wouldn’t make it out of Walter Reed National Military Medical Center. Those close to Mark Meadows, Trump’s chief of staff at the time, said he feared the president would die. Meadows disclosed in a book released earlier this month that the former president’s blood-oxygen levels dropped “dangerously” low during his bout with the virus.

The federal government is pushing everyone who’s eligible to get booster shots as the omicron variant spreads across the country. Both Pfizer and Moderna have said their booster shots appear to protect against the new variant, which preliminary data suggests is more contagious than its predecessors.