President Donald Trump has called for a “major investigation” into several celebrity endorsements former Vice President Kamala Harris received during the 2024 presidential campaign, suggesting without evidence that some of the celebrities were illegally paid for their endorsements.

Some of the celebrities have publicly denied denying being paid any fee at all, and experts say there’s no FEC law barring campaign payments for endorsements.

Among the celebrities the president suggests were illegally paid for their endorsements are Oprah Winfrey, Bruce Springsteen and Beyonce, each of whom appeared at Harris campaign events last year.

“Candidates aren’t allowed to pay for ENDORSEMENTS, which is what Kamala did, under the guise of paying for entertainment,” Trump wrote in a pair of social media posts Monday.

The Harris campaign paid production companies founded by Winfrey, Springsteen and Beyonce for services provided during and after the 2024 election — but Winfrey and Beyonce’s mother, who runs her production company, both said the payments were for production costs associated with the events they participated in.

Campaign law experts told ABC News that the Federal Election Commission has no regulations against federal campaigns paying celebrities or influencers for endorsements, nor would they be considered illegal contributions as Trump suggested — as long as those payments are properly disclosed. The Federal Trade Commission oversees disclosure obligations for paid endorsement, the experts said.

Campaign finance disclosures show the Harris campaign paid Winfrey’s company, Harpo Productions, a total of $1 million for “event production” on Oct. 15, 2024, roughly a month after Winfrey interviewed Harris at a “Unite for America” campaign event in Detroit in September.

“I did not take any personal fee. However, the people who worked on that production needed to be paid and were. End of story,” Winfrey said in a social media video in response to Trump’s accusation.

The Harris campaign paid Beyonce’s company, Parkwood Production Media LLC, $165,000 on Nov. 19, 2024, weeks after Beyonce took the stage at a Harris campaign rally in Houston and publicly endorsed Harris, according to campaign records.

Beyonce’s mother Tina Knowles, in a social media video, said the accusation that her daughter was paid for her endorsement is a “lie,” adding that Beyonce also paid for the flights for herself and her team to and from the event.

The Harris campaign paid Springsteen’s production company, Thrill Hill Productions, Inc., roughly $75,000 for “travel and event production” on Nov. 19, 2024, roughly a month after he performed at a Harris campaign rally in Georgia, records show. Springsteen has not publicly addressed the campaign’s payment to his company.

Last year as unfounded claims about the Harris campaign’s payments for celebrity endorsements spread, senior campaign adviser Adrienne Elrod told Deadline, “We do not pay. We have never paid any artist and performer. We have never paid a fee to that person.”

Noting that FEC rules require campaigns to pay fair market value for the ancillary costs of holding events, Elrod told Deadline the campaign has paid “for any ancillary costs for that performance” and that “there are laws that have to be followed that we have followed religiously on this campaign.”

Among the celebrities who have appeared and performed at Trump’s campaign events over the years, ABC News has found no records of the Trump campaign or Trump’s other entities paying them or their companies.

Country singer Lee Greenwood, whose song “God Bless the USA” is frequently featured at Trump rallies and who has performed at Trump campaign events himself, stated on social media in November that he had not been compensated in “any form” by the Trump campaign or the Trump Organization for his campaign appearances, saying he’s “happy to have stood by” Trump.