Prince William is PISSED OFF at his little brother for what might seem like a super trivial thing — but it’s actually extremely important!

According to a new report, Will is beyond angry with Prince Harry and Meghan Markle because they apparently refuse to refer to his wife Princess Catherine by her full name! That’s right — Harry and Meghan are said to still refer to Kate Middleton as “Kate” instead of “Catherine” or Princess Catherine. Seems minor, right? Well, that’s actually a HUGE problem for William!

According to The Daily Beast, the Prince of Wales first really picked up on the Kate/Catherine conundrum in the “get well soon” messages the Spare author and the Suits alum sent to the princess after her cancer diagnosis became public earlier this year.

The princess has been pretty adamant in recent years about wanting to be referred to as Catherine, her birth name, rather than the shortened Kate of which she was known for so many years. When she started dating and then married William, she rose her worldwide profile as part of the royal family as “Kate Middleton”. It’s only recently that anyone has begun calling her Princess Catherine, but it’s what she prefers apparently. Catherine is more official, more mature, more dignified — all that stuff. Especially as Catherine and William prep to one day ascend to the throne together!

But according to that outlet’s insider on Tuesday, Harry and Meghan referred to her only as Kate in their post-diagnosis well wishes earlier this year. And that was seen by William as an “entirely unnecessary and deliberate irritation.”

Ouch!!

As for why William is so angry at the perceived affront from his estranged brother and sister-in-law, the source explained:

“William takes offense at people calling Catherine ‘Kate’ because she has asked to be known as Catherine. It’s a fairly simple wish to respect. I’m sure Meghan wouldn’t like it if William started publicly calling her ‘Meghan Markle.’”

Are… we not supposed to call her Meghan Markle, either??

A close friend of William’s also spoke to the news outlet, levying this revelation about how the chosen name refusal points to much deeper issues between the brothers:

“The fact that Harry and Meghan were unable to bring themselves to use her chosen name, even when they were sending her get-well-soon messages after her cancer diagnosis, was noted.”

Oof!

Now, you might react to this like we did at first — which is to be amazed at how trivial the distinction is between Kate and Catherine. And especially among family members! It’s tough when you’ve known someone by one name for so long. But the Kate-Catherine debacle is a VERY long-standing issue for William. That first Daily Beast source explained how everyone very well knows “that it is one of the things that pushes his buttons.” So, why keep doing it if you know it’s going to piss William off?! This is a message in writing! You can edit it! It’s not a slip of the tongue!

That source continued:

“Pushing his buttons while he was going through his wife’s cancer seemed an entirely unnecessary and deliberate irritation. I wonder if the private card began, ‘Dear Kate…’”

And a third source summed it up better than we ever could:

“No one’s saying it’s responsible for all the trouble, but deliberately calling someone by a name they don’t like is just bloody rude. If Harry and Meghan were serious about healing their issue, a good first step would be to call her Catherine.”

Good point!!

And look, we get it, nicknames are a thing. “Robert” becomes “Rob” or “Bob” or “Bobby.” And “William” morphs into “Bill” or “Will” or “Billy.” So it goes! But if the person in question wants you to use their given name, and has been asking politely to be referred to by that name for a long time… why not just do it?! It’s the polite thing to do! Right?