But, before you start negotiating a peace treaty, know that it's all in good fun to promote the Invictus Games, a Paralympic-style games for wounded veterans which will take place in Orlando in May.
The Kensington Palace's official Instagram page posted a hilarious video on Friday that opens with The Queen (yes, the actual Queen) and Harry watching a video sent to them by United States Commander-in-Chief and First Lady Michelle Obama.
"Oh, it's from Michelle," he tells his grandmother after a message comes in from "F.L.O.T.U.S." while "Hail to the Chief" plays as the ringtone. "Would you like to watch it together?"
After the Queen agrees, the video opens with the couple crossing their arms, looking serious. Three United States servicemen and women stand behind them.
"Hey, Prince Harry. Remember when you told us to bring it at the Invictus Games?" Michelle asks, before Barack tells him to "be careful what you wish for." In the background, a military member motions his hand like he's dropping the microphone and says, "Boom."
Michelle also tweeted the video at the Kensington Palace Twitter page.
That started a fun social media banter between the two sides.
"Wow @FLOTUS and @POTUS, some @weareinvictus fighting talk there! You can dish it out, but can you take it? - H.," Harry tweeted via the Palace's page.
Harry and Queen Elizabeth hardly seem flustered from the Obama family's confidence upon watching their video. Her smiling response: "Oh, really, please." Harry then looks at the video camera and does the same hand gesture and says, "Boom."
"Unfortunately for you @michelleobama and @barackobama I wasn't alone when you sent me that video - Prince Harry," he humorously captioned the twitter post of the video of the video.
Earlier this year, Michelle confirmed that she would be on hand with Dr. Jill Biden, the wife of of Vice President Joe Biden, to watch the event created by Harry.
"With Prince Harry's leadership, I hope that the world will join us in celebrating these incredible athletes and supporting all our service members, veterans, and their families," the First Lady told People in March. "I'm excited to cheer on the Warriors of Team USA in Orlando as they represent our nation and their brothers and sisters in arms."
Perhaps Michelle can give Team USA some trash talking lessons while she's there.