Top Gun: Maverick star reveals the "rules" he had to follow when meeting Prince William and Kate Middleton

All eyes were on the Duke and Duchess of Cambridge as they attended the Top Gun: Maverick premiere in London's Leicester Square earlier this month.

But for actor Jon Hamm it was an "anxiety-producing" moment as he learned that meeting royalty comes with its own set of unique rules.

Appearing on Live with Kelly and Ryan, the 51-year-old star said: "It's a little anxiety-producing because they give you these rules that you're meant to sort of follow.

"You're meant to say, 'Your Royal Highness' — if they offer their name, then you can use their name, but you can't do it first."

He continued: "And you can't offer your hand, they have to offer their hand. Then you have to bow, but you can't bow too low."

Hamm also admitted his costar Miles Teller was distracted by the Duke of Cambridge's eyes.

"He geeked out a little on Prince William's eyes. I remember coming back afterwards, he's like, 'They're so blue. I got lost in his eyes.'"

The actor then quipped: "I didn't think we were allowed to look him in the eye."

Top Gun: Maverick, which has so far received rave reviews from critics, sees Hollywood star Tom Cruise reprise the role of US naval aviator Pete Mitchell and is being released 36 years after the 1986 original.

Other stars include Miles Teller, Jennifer Connelly, Monica Barbaro, Val Kilmer and Glen Powell.