President Donald Trump is calling for a federal investigation into former Vice President Kamala Harris's presidential campaign and the celebrity endorsements Harris received during that campaign. Stars like Beyoncé,

Trump's call comes amid his feud with Springsteen as the president appeared to threaten the rock star for calling the the administration "corrupt, incompetent, and treasonous" during recent U.K. concerts.

The president claimed without evidence on Monday that Kamala Harris had violated campaign-finance law, essentially by paying superstars for endorsements “under the guise of paying for entertainment.”