The rain did not dampen the King's spirits as he toured Old Spitalfields Market after visiting the nearby South by SouthWest London (SXSW London) festival.
And now a clip of the monarch's soggy engagement has sparked comments from royal fans as Charles stopped to speak with as many members of the public as possible.
The video, shared on the royal family's Instagram page, showed the unfazed King standing in a puddle as he shook hands with people, holding an umbrella in his other hand to shelter from the downpour.
© Getty"Was the King seriously standing in a puddle of rain to shake hands? Class act!" one social media user remarked, while another replied: "Oh Lord! I noticed just now! Wow - appreciated the sacrifice."
© Getty Images for SXSW LondonOthers commented: "Love the way that huge puddle didn’t bother him."
Is the King a Swiftie?
The footage from the King's engagement was also overlaid with Taylor Swift's song "London Boy," which also caught royal fans' attention.
"I don’t know what I love more. The fact that he’s standing in puddles outside in the rain to talk to people. Or that this is more evident that His Majesty is a Swiftie," one said.
Another added: "Love the fact they used a Taylor Swift song. Princess Charlotte approved."
© InstagramThe US popstar is no stranger to royalty having met the Prince of Wales twice and his eldest children, Prince George and Princess Charlotte.
Prince William was spotting dad-dancing in the crowd with George and Charlotte during Taylor's iconic Eras tour in June 2024.
The royal trio then met the singer backstage, with Charlotte sporting a sparkly dress and braids in her hair.
© Getty ImagesThe youngster is also a fan of friendship bracelets – an accessory which has become synonymous with Swifties – and has made them for her family members.
© GettyThe King sported a braided bracelet during his visit to the Channel Islands last summer, while William donned a personalised "Papa" version for his visit to Cape Town last November.
