Prince Harry has been facing mounting pressure to have his visa application made public after admitting past drug use in his explosive memoir "Spare."

The Heritage Foundation, a conservative think tank based in Washington, D.C., is urging that the Duke of Sussex’s visa application be released. The goal is to determine whether the 38-year-old declared his previous drug use, the U.K.’s Daily Mail recently reported.

The father of two, who lives in California, made a surprise appearance at London’s High Court Monday. The British royal, along with several prominent figures, are suing Associated Newspapers Limited, publisher of the Daily Mail and Mail on Sunday, for illegal information gathering.

PRINCE HARRY SAYS PSYCHEDELIC DRUGS HELPED HIM — BUT WHAT ABOUT THE RISKS AND DANGERS?

Several legal experts told Fox News Digital Harry is not at high risk of having his visa overturned given the timing of when these incidents occurred.

"I see no risk to Harry’s status in the United States based on his admitted drug use while he was younger," said legal analyst Chris Melcher, partner with Walzer Melcher & Yoda.

"Everyone should be accountable to the same standards, and no visa applicant would expect to be denied entry based on the recreational use of illegal drugs in the past when they suffered no conviction for that offense."

Los Angeles-based criminal defense attorney Silva Megerditchian agreed.

"Immigration officials would have a difficult time giving people visas if mere admissions to experimental drug use were an issue, especially once they are living in the country," she pointed out.

Nile Gardiner, the director for the Margaret Thatcher Center at The Heritage Foundation, told Fox News Digital that it's in "the public interest" to both know and ensure that the royal's visa application was "entirely accurate." Gardiner is a former aide to the former U.K. prime minister.

"Harry outlined in significant detail his history of drug use in his memoir 'Spare,'" Gardiner explained. "We want to establish that Harry was truthful in regards to his application. This is a serious matter here. We believe there's a clear public interest in the release of Harry's immigration application.

"The Heritage Foundation is calling for accountability and transparency from the Biden administration in releasing Prince Harry's immigration application," Gardiner added. "It's important to establish that Prince Harry did not receive any special treatment with his application. Just because he is a prince does not mean that he should be treated any differently from any other person applying to the United States."

A State Department spokesperson told Fox News Digital that "visa records are confidential under Section 222(f) of the Immigration and Nationality Act (INA); therefore, we cannot discuss the details of individual visa cases."

Samuel Dewey, the lead attorney representing The Heritage Foundation, told Fox News Digital in response: "On the legal issue, the state department is citing a statute that doesn’t have any application here because we are seeking records from DHS (Department of Homeland Security). A-files are frequently made public. If you go to the USCIS (U.S. Citizenship and Immigration Services) Reading Room you will see a whole category is for famous individuals A-files. The most recent one is the vice president's mother."

While Harry is in the clear, Melcher said he isn’t surprised the royal's U.S. visa status is being scrutinized. The prince lives in the wealthy, coastal city of Montecito, California, with his wife Meghan Markle and their two young children, Prince Archie and Princess Lilibet.

"The U.S. Immigration and Naturalization Act, 8 U.S.C. 1182(a)(2)(A)(i), states that an immigrant is ineligible to receive a visa or to be admitted to the United States if the person was ‘convicted of, or who admits having committed, or who admits committing acts which constitute the essential elements of … any law or regulation of a State, the United States, or a foreign country relating to a controlled substance,’" Melcher explained. "There is an exception if the person was under the age of 18 when the crime was committed or if the maximum penalty available for the offense was one year.

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"Based on a literal reading of U.S. Immigration law, Harry may be excluded from the United States based on his admission to using magic mushrooms, as the U.S. Immigration and Naturalization Act provides that a person is ineligible for admission to the U.S. if they have admitted to the use of a controlled substance in violation of the law of a foreign country as an adult if the available prison sentence of that violation is at least one year," Melcher added. "Magic mushrooms are classified as a controlled drug under English law, so his possession of the drug before he ingested it could qualify as an admitted offense that makes him ineligible for admission to the United States.

"But it is unclear whether Harry was asked about his drug history in any immigration interview and, if so, whether he admitted the magic mushroom," Melcher continued. "It seems unreasonable to apply the law to an admission of drug use in an interview with a reporter rather than to a government official. Most likely, the issue never came up in any immigration interview because Harry was not convicted of any drug offense, he served with distinction in the military and there is no reason to suspect that he is a drug addict."

Megerditchian did warn that Harry, like any high-profile figure, should be mindful of what he publicly shares.

"As a criminal defense attorney representing clients with drug issues, I work closely with immigration attorneys who deal with the consequences of their status in the United States," she said. "At this point, Harry’s mere admission of experimental drug use without any law enforcement contact should not affect his standing in any way.

"In general, high-profile figures should always be careful making admissions about illegal drug use," she warned. "You never know how that can affect you if you are ever arrested in the future."

In his memoir, Harry admitted that, at age 17, he used cocaine several times "to feel. To be different." He also acknowledged using cannabis and magic mushrooms, which made him hallucinate that a toilet was talking to him.

Gardiner argued that the key issue here is "whether or not the application that Harry made match exactly the details he put in his own memoir."

PRINCE HARRY ADMITS PSYCHEDELIC DRUGS HELPED HIM 'DEAL WITH THE TRAUMAS' OF THE PAST

"When people apply into the United States, they are asked specifically about drug use," said Gardiner. "The issue here is his usage of drugs and whether it was fully reported to U.S. immigration authorities ... whether he was fully truthful and transparent in his application and, secondly, whether he received any preferential treatment from officials with regard to his application."

A spokesperson for the Duke of Sussex didn't immediately respond to Fox News Digital's request for comment.

During a candid online chat with trauma expert Gabor Maté earlier this month, Harry admitted that psychedelic drugs helped him acknowledge his mother, Princess Diana's death, and how to move forward.

"It was the cleaning of the windscreen, the removal of life’s filters — these layers of filters — it removed it all for me and brought me a sense of relaxation, relief, comfort, a lightness that I managed to hold back for a period of time," Harry explained.

"I started doing it recreationally and then started to realize how good it was for me," he continued. "I would say it is one of the fundamental parts of my life that changed me and helped me deal with the traumas and the pains of the past. They’re unlocking so much of what we’ve suppressed."

Therapy using psychedelic drugs, including the naturally occurring psilocybin compound found in mushrooms, is growing in popularity.

Hallucinogenic drugs are becoming so accessible that states are working on laws to not only decriminalize, but also legalize regulated psychedelic therapy programs.

Gwyneth Paltrow once said that psychedelics would be the new trend in the wellness industry. Michelle Rodriguez took psychedelics to cope with the death of her "Fast and Furious" co-star Paul Walker and Paul McCartney claims he saw God during an acid trip.

Country musician Kacey Musgraves admitted that her songs "Slow Burn" and "Mother" were inspired by hallucinogens.

PRINCE HARRY MAKES COURT APPEARANCE IN CASE AGAINST BRITISH TABLOIDS

Green Bay Packers quarterback Aaron Rodgers used psychedelics to treat his overwhelming fear of mortality.

"I definitely had a fear of death," he said last year. "And ayahuasca, and psilocybin actually, really helped me with that and relieved a lot of the stress around the idea of needing to accomplish things before I actually die … and taking away some of that fear.

"I think when you’ve seen the other side, it makes the idea of death more of a passage and less of an ending," Rodgers explained.

The Duke and Duchess of Sussex stepped back as senior royals in 2020, citing what they described as unbearable intrusions and racist attitudes of the British media. It’s unclear whether the couple will attend King Charles’ coronation at London’s Westminster Abbey May 6.