LeBron James criticized for draping sweaty arm around Kate Middleton's shoulder (PHOTO)

LeBron James may be considered The King on an NBA basketball court but when it comes to mixing with the real royals, he might need a lesson in protocol.

James got a prized snapshot for his photo album when he posed with Prince William and Kate Middleton after the Cavaliers-Nets game in Brooklyn last night, but he also got called for a flagrant foul by putting his arm around the Duchess of Cambridge's shoulder during the shot.

Prince William and Kate stood with James inside Barclay's Center after the game Monday night — where they were presented with a tiny jersey for Prince George.

But as the camera flashes went off, a sweaty James put his arm around the Duchess' shoulder — a huge breach in etiquette.

LeBron James breaks royal protocol with arm around Kate's shoulder http://t.co/TFV7C8Om2Y pic.twitter.com/xL2IixBudt
— The Telegraph (@Telegraph) December 9, 2014

Etiquette expert William Hanson told MailOnline: "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 think they’d have learned by now." 

Appearing alongside the royals un-showered and in a sweaty top is something many regard as bad form. 

"A shower would have been preferable but he had just finished a game," said Hanson. "So even more reason for him not have opened his pits by lifting his arm and placing it around Her Royal Highness!"

The King Meets The Royals これは洒落が効いてますな♪笑 NBAの王様が英国王室の皇太子夫婦と面会する！ http://t.co/bQWiznXZBL #nba #lebron
— スー @ 相互フォロー募集中♪ (@scrBasketBlog) December 9, 2014

A lot of harrumphs were sounded in 2012 when centuries-long protocol was broken by Michelle Obama putting her arm around the Queen at a Buckingham Palace G20 reception.

And everyone got over that.

Where's LeBron? At a Knicks game of course (PHOTOS)

This might be the closest thing to the Knicks actually getting LeBron James a perch on their bench, but at least there was a real winner sitting in Madison Square Garden on Sunday.

Looking more like Where's Waldo than King James, then Cavaliers star took in the Knicks 103-99 loss to the Portland Trail Blazers last night at the Garden.

And he showed New York fans that while the Nets might have Prince William and Duchess Kate Middleton attending a game at Barclays Center in Brooklyn on Monday, Manhattan's team can still draw some royalty of their own — NBA royalty.

http://t.co/UAuo8ElFGm #nba LeBron James says he wants ‘I can’t breathe’ shirt as protests spread to pro sports pic.twitter.com/0TJ4LAVv0w
— WordLink #NBA (@NBAbyWordLink) December 8, 2014

According to Carmelo Anthony, James took in the game on his off day as a way to show his “support” for their friendship.

Hopefully, that friendship is tighter than the Knicks defense. The home team lost after blowing a fourth-quarter lead.

LeBron James wants an ‘I can’t breathe’ t-shirt for Cavs-Nets game: Report

While many eyes will be looking up at a heavily guarded private suite occupied by members of the royal family at Barclays Center Monday night, one member of NBA royalty will try and get people to notice him as a man of the people down below during pre-game warmups.

LeBron James said he is looking for a way for a way to protest the Eric Garner decision, and wants to get a "#I can't breathe" t-shirt to wear before the Cavaliers take on the Nets.

Britain's Prince William and his pregnant wife, Duchess Kate Middleton, will be in attendance for the game featuring King James himself on this already over-hyped night.

James has already spoken out about the death of Garner and a grand jury‘s controversial decision not to indict the responsible officers.

On Sunday, James was asked about the t-shirt worn recently by Bulls point guard Derrick Rose.

The message on Rose’s shirt, “I can’t breathe,” is a reference to Garner’s words as he was choked while being arrested for selling untaxed cigarettes. Detroit Lions running back Reggie Bush also wore a shirt with the phrase written on it on Sunday.

“It was spectacular,” James said about Rose’s shirt, which he wore in pre-game warmups Saturday night. “I loved it. I’m looking for one.”

It shouldn't be hard to find. They’re reportedly going for $9.99 on eBay.

Will he wear it Monday at Brooklyn's Barclays Center, where the Royals will be in attendance and where protesters gathered outside just days earlier?

Even without Jay Z and Beyonce who will also be there, expect a wild scene.

NBA donated $1 million for William and Kate to attend Cavs-Nets game: Report

In a bid to make the bring basketball to an even bigger worldwide audience, the NBA is donating $1 million dollars to Prince William and  Kate Middleton's charity for attending a Cavaliers-Nets game featuring LeBron James at Brooklyn's Barclays Center next month.

The NBA honchos' generous donation to the Duke and Duchess' new conservation charity is reportedly a big "thank you" for attending the already high-profile game during the Royal Couple's three-day trip in New York City, according to MailOnline.

The decision by the couple to attend that particular game means the Royals will get to meet King James — still the NBA's reigning star.

NBA insiders believe that the image of the royal couple at the game inside Barclays Center will be shown around the world, helping the sport gain new fans.

"It's an incredible publicity coup for the NBA,'"an insider told MailOnline.

"The images of them all together will be seen all over the world — it's a marketing man's dream. A million bucks is a small price to pay for the publicity the NBA's going to get."

Friends say that Kate and William had expressed an interest in attending a basketball game at legendary Madison Square Garden when they were planning their December 7-9 visit to the city.

But the couple snubbed the New York Knicks vs. Portland Trailblazers game on December 7 in favor of seeing LeBron play the following night.

"Kate and William are both big sports fans'," explained the friend. 

"And although basketball isn't big in Britain, William has heard of LeBron James... although Kate apparently had no idea who he was!"

NBA Commissioner Adam Silver will also be present at the game and is said to be beside himself with excitement at the public relations coup.

And while most attention-seeking celebrities usually sit courtside, the Duke and pregnant Duchess are expected to be viewing the game from the relative safety of a private box.

They will probably meet music royalty when Beyonce and former Nets minority owner, Jay Z, are expected take in the action on the same night.

That might be the photo-op of the year.