Former President Donald Trump is calling for a “major investigation” into alleged improper payments to celebrities who endorsed Vice President Kamala Harris during her 2024 presidential campaign.

In a Truth Social post, Trump questioned whether stars like Bruce Springsteen, Beyoncé, Oprah Winfrey, and Bono were illegally compensated for campaign appearances under the pretense of performance fees. “Candidates aren’t allowed to pay for endorsements,” he wrote, claiming the Harris campaign used entertainment expenses to cover what he called “unlawful” campaign contributions.

Trump alleged Beyoncé was paid $11 million to briefly appear at a rally without performing and accused Harris’s team of “illegally” boosting her campaign with celebrity support. The campaign denied the payments were for endorsements, citing event production costs. FEC records show $165,000 went to Beyoncé’s company, Parkwood Production Media, after the event.

Oprah’s team also denied any improper payment, saying compensation covered production expenses.

Trump’s accusations follow a series of high-profile Harris events after Biden withdrew from the race. Harris responded to recent news of Biden’s prostate cancer diagnosis, offering support and prayers for his recovery.