WASHINGTON, United States (AFP) — Billionaire Elon Musk was expected in court in Philadelphia on Thursday, after a judge ordered him to attend a hearing in a lawsuit seeking to halt his $1 million giveaways to registered US voters in swing states.

Philadelphia’s chief prosecutor Larry Krasner lodged the suit on Monday, calling Musk’s project “an illegal lottery scheme”, with the judge in the case ruling Wednesday that the billionaire is required to appear in court.

“It is further ordered that all parties must be present at the time of the hearing,” judge Anne Marie Coyle said.

Musk stirred controversy after he announced the daily contest this month, prompting the Justice Department to warn that it may violate federal law which prohibits paying people to register to vote.

Musk, 53, who owns SpaceX and X, formerly Twitter, has thrown his millions, time and considerable influence into backing Republican presidential candidate Donald Trump since endorsing him in July.

Musk, the world’s richest man, has reportedly donated $118 million to his personal pro-Trump political action committee, an organization which collects funds for elections.

He has also appeared on stage with Trump at a campaign rally in Pennsylvania and hosted a series of town halls on his own in the battleground state, seen as critical in the November election.

Musk, who previously supported Barack Obama but has become increasingly conservative in recent years, peppers his 202 million followers on X daily with messages championing Trump and denigrating his opponent, Vice President Kamala Harris.