U.S. President Donald Trump on Monday announced plans to launch a “major investigation” into Vice President Kamala Harris over alleged payments made to celebrities who supported her unsuccessful 2024 presidential campaign.

“Candidates aren’t allowed to pay for ENDORSEMENTS, which is what Kamala did, under the guise of paying for entertainment,” Trump wrote on his Truth Social platform. “I am going to call for a major investigation into this matter.”

Harris, who took over as the Democratic nominee following President Joe Biden’s withdrawal from the race, enlisted high-profile support from celebrities such as Beyoncé and Oprah Winfrey during her campaign.

Winfrey reportedly received $1 million through her production company for costs associated with hosting a campaign event for Harris. Meanwhile, the Harris team denied widespread rumors that pop icon Beyoncé was paid $10 million to appear at a campaign rally.

Campaign finance disclosures listed a single endorsement-related payment of $75 to an environmental advocacy group, but Trump claims more significant expenditures were masked as entertainment costs.

The president, who won re-election decisively, received limited support from Hollywood but maintained backing from a niche group of prominent conservative and libertarian influencers, including podcast host Joe Rogan.

On Monday, Trump also criticized Bruce Springsteen, alleging the rock star was paid by the Harris campaign to perform at a rally in Georgia weeks before the election.

“How much did Kamala Harris pay Bruce Springsteen for his poor performance during her campaign for president?” Trump asked. “Why did he accept that money if he is such a fan of hers?”

The comments come days after Trump reignited his long-standing feud with Springsteen, following the musician’s remarks at a concert in the U.K. in which he described the current U.S. administration as “corrupt, incompetent, and treasonous.”

Trump, 78, fired back on social media, calling the music legend “highly overrated.”

Springsteen, known for his progressive political stance, had publicly endorsed Harris after she replaced Biden on the Democratic ticket.