Prince Harry is set to be the subject of a case in US court today (Tuesday, May 6) due to how he answered questions about drug-taking on his US visa form.

He could be under threat of removal from the country, as lawyers are due in a federal courtroom to demand the US government release the Duke of Sussex's US visa application form.

An American conservative political research group, the Heritage Foundation, were the group that filed the lawsuit.

In his memoir, Spare, which was released earlier this year, Prince Harry admitted to having used cocaine, marijuana and magic mushrooms, Sky News reports.

The Argus: It was Prince Harry's admission that he used drugs in his memoir Spare that has caused the lawsuit to happenIt was Prince Harry's admission that he used drugs in his memoir Spare that has caused the lawsuit to happen (Image: PA)

Under US law, admission of, or evidence of past drug use, can be grounds to reject a visa application.

Prince Harry's latest high-profile case of visa being questioned

Prince Harry's visa application is the most recent and most high-profile example of the process being called into question.

The celebrity chef Nigella Lawson was eventually granted a visa after a long process after previously admitting she had taken cocaine and marijuana.

Additionally, the musician Pete Doherty, who has a string of drug convictions, was allowed to fly to the US in 2010 before he was sent back home on the next flight.

The counsel for the Heritage Foundation, Sam Dewey said: "We view it as a very serious question - why he's let in, no problem, given everything that we know [about his drug use] which we've explained in detail, and others aren't let in."

The hearing could last weeks but ultimately the judge must rule on whether it is in the public interest to release the prince's application form, or parts of it

Following that scenario the public will then find out if he either claimed he had never taken drugs, or he admitted taking them and the US government allowed him in any way.

At the same time as this, the Duke of Sussex is also giving evidence in UK court against the Mirror Group Newspapers over allegations of phone hacking.