Prince Harry’s US visa is expected to expire sooner than later and in order to get it renewed he’d need a letter from his dad, says immigration lawyer Charlotte Slocombe.

It’s not known what kind of visa Harry has, but it’s it’s most likely an A-1 or an O-1, says the lawyer.

Ms Slocombe explains the difference between the two, saying: “Visa validity for an A-1 should be valid for 5 years so, if he indeed holds an A-1, it will likely be coming up for renewal soon.”

She adds: “Interestingly, he would need a letter from the King himself to make this application.”

“Another notable visa option for Harry would be the O-1, which I suspect is the visa he holds, is for individuals with recognised extraordinary ability in their field.”

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Harry and his father, King Charles, haven’t been on the best of terms, so asking for a referral letter may be awkward for the duke.

Just recently, it was reported Harry extended an olive branch to both Charles and his brother Prince Wiliam, but it came across a "self-serving," and it was more likely a PR stunt.

Harry will be in the UK this week for the Invictus Games 10-Year Anniversary, he's hoping to meet-up with Charles, it's being said.