LeBron James Broke Royal Protocol By Putting His Arm Around Duchess 'Kate Middleton'

Catherine Duchess of Cambridge and Prince William with Lebron James at the Brooklyn Nets vs. Cleveland Cavaliers, NBA Basketball game on Dec. 8, 2014 in New York.

To an American eye, there was nothing strange about a sweaty LeBron James putting his arm around Kate to pose for a photograph after his Cleveland Cavaliers played the Brooklyn Nets on Monday evening. To the British, though, merely touching the Duchess of Cambridge represents a serious breach in etiquette.

Etiquette expert William Hanson told MailOnline that although the Duchess is unlikely to give Mr James the cold shoulder, he still should have kept his arm away from her.

He said: 'Although I am sure the Duchess of Cambridge won’t have worried about it, Mr James should not have put his arm around her. 

'Americans are much more tactile than we Brits and this is another example of an American being too touchy feely with British royalty. You’d have thought they’d have learned by now.'

The eyebrow-raising moment followed the royal couple meeting pop royalty Beyoncé and husband Jay-Z - and Prince William visiting the White House for a meeting with President Barack Obama.