The International Triathlon Union has mixed up the Brownlee brothers by sending a letter of congratulations to Jonny following Alistair's win in Leeds at the weekend.
The younger of the Brownlee brothers shared the letter on social media, simply writing "#awkward".
The letter, signed by ITU president Marisol Casado, is clearly addressed to 'Jonathan Brownlee' and says it is to "congratulate you on your recent victory at Columbia Threadneedle World Triathlon in Leeds".
But it was elder brother Alistair who led the Dewsbury-born brothers home in a one-two finish, a repeat of the inaugural staging of the race a year earlier.
Alistair, 29, finished in a time of one hour, 46 minutes and 51 seconds, 12 seconds ahead of the 27-year-old Jonny, with the pair more than a minute clear of the rest of the field.
Alistair has a long history of getting the better of his younger brother in competition, and took gold to Jonny's silver in last year's Olympics in Rio.
