Prince Harry and Prince William are both keen sportsmen, but there's one activity the Prince of Wales always beats the Duke of Sussex in.
READ: How Prince William's major surgery left him scarred for life
During a 2009 interview with BBC Newsround, Prince William boasted about his arm-wrestling skills. When asked who would win the test of strength, the Prince of Wales said: "You know the answer to that. It's not even a contest. Obviously I'd win. Obviously."
WATCH: The Crown releases official season 5 trailer
He went on to share it wasn't that he was stronger than Harry, explaining: "As the bigger brother you have that psychological power over your brother, you see."
READ: Princess Diana's friend reveals fears for Princes William and Harry over controversial decision
MORE: King Charles has a very special wish for his granddaughter Princess Charlotte
With brotherly competition in mind, we wonder if Prince George and Prince Louis will partake in arm wrestles too, and whether George will be triumphant.
The future king and Prince Harry share several sporting hobbies, including boxing and polo, with Harry even playing polo at a professional level since moving to California.
Prince William and Harry are competitive in sport
Boxing is a sport William was a big fan of in his younger years, but an injury hampered his progress.
SEE: Proof Prince Louis gets his cheeky streak from Prince William in rare unearthed video
At an engagement in mid-October, William squared up to a punchbag, displaying never-before-seen skills.
Princes Harry and William both enjoying boxing
As to why we've never been privy to William's boxing skills, an attendee at the event revealed: "He's got a little knuckle injury, so he wouldn't be taking it up anytime soon."
Prince Harry has contiuned with the sport, and said he enjoys it to help relieve tension, explaining on Bryony Gordon's Mad World podcast: "Everyone was saying boxing is good for you and it's a really good way of letting out aggression.
"And that really saved me because I was on the verge of punching someone, so being able to punch someone who had pads was certainly easier."