Prince Harry's past drug use detailed in his explosive memoir should lead to the release of his immigration paperwork, an American conservative think tank has argued in a Washington court.
The Heritage Foundation appealed to US District Judge Carl Nichols for a quicker response to a records request the US government has so far deemed private.
Mr Nichols told the foundation and the Department of Homeland Security to work on the speed of the response and said he would rule if they could not reach an agreement on their own.
The Duke of Sussex moved to Southern California with his wife Meghan Markle and their young family in 2020 after they left royal life.
In his memoir Spare he detailed his past drug use, saying he took cocaine several times starting around age 17 in order "to be different".
He also admitted using cannabis and magic mushrooms.
The US routinely asks about drug use on its visa applications.
This has led to travel headaches for several celebrities including chef Nigella Lawson and singers Amy Winehouse and Pete Doherty.
Acknowledgement of past drug use does not necessarily bar people from entering or staying in the country.
Request denied because group lacks Harry's permission
The Heritage Foundation sent a public information request to the Department of Homeland Security asking for Prince Harry's immigration records.
They argue there is "intense public interest" in whether the prince got special treatment during his application process.
The conservative think tank also linked those questions to wider immigration issues in the US such as those surrounding the southern border with Mexico.
The request has largely been denied since the group does not have Prince Harry's permission to get the private information.
"A person's visa status is confidential," said John Bardo, an attorney for the Department of Homeland Security.
The agency's policy allows the release of information about issues of public interest, but the agency argued media coverage of how Harry's drug use connects to his visa status in the US has not been widespread among mainstream American publications.
'This is about accountability and transparency'
"This case is all about the enforcement of US Immigration Law and certainly Prince Harry is one of the most high profile figures, one of the most well-known figures in the world right now including here in the United States," Dr Nile Gardiner from the Heritage Foundation told Sky News's US correspondent Mark Stone.
"But at the end of the day, this is about accountability and transparency and openness on the part of the US administration, with regard to an immigration application by a high-profile individual.
"There is a US public interest in this. But without a doubt, I think that a key factor here has been Prince Harry's memoir Spare and his revelations about his own drug use; he's put it all out there.
"Let's see whether that exactly matches what he put on his immigration application. Because if it doesn't, that's perjury, that's a criminal offence, actually, and everyone should be held to account before the law. No one should be treated any differently."