Much like the main man himself, Sherlock usually has every little detail mapped out to the extreme... so quite how this whopper of a blooper got through is a bigger mystery than anything Holmes has ever solved.
In the New Year's Day (January 1) series four opener "The Six Thatchers," John Watson (Martin Freeman) returned to update his blog about his and Sherlock's (Benedict Cumberbatch) adventures.
Except he was not doing that at all, as one keen fan noticed.
The screencap from the episode clearly sees Watson staring at a photo file of his webpage - heck, even the title "JOHN BLOG PAGE.jpg" is showing in the top left corner.
Come on producers, this is the age of the internet! Did you honestly think you could get away with nobody noticing?
As well as that elementary mistake, it's also worth re-watching the episode to spot the teaser about Toby Jones's villain Culverton Smith (opens in new tab)—courtesy of a bus stop advert—who makes his first appearance as a major villain in next week's episode.
While we've yet to see the baddie on screen, Freeman has promised that Smith could be "even more creepy than Moriarty," so consider yourself warned.
Sherlock continues on BBC One on Sunday, January 8 at 9pm.
The Best Rain Boots, According to Fashion Editors
Stay dry *and* look cute!
By Julia Marzovilla
Mexico City, A Vibrant Cultural Hot Spot, Is the Perfect Travel Destination
This epicenter of art, history, and food should be on every culture enthusiast's bucket list.
By Gabrielle Ulubay
Can Light Therapy Get Rid of My Acne?
Blue and red light are where it’s at.
By Samantha Holender
The 78 Best Celebrity Couple Halloween Costumes of All Time
Honestly, we're impressed.
By Charlotte Chilton
22 Captivating Films About Royal Life
Once you've finished 'The Crown,' cue up one of these royally good films.
By Nicole Briese
Who Is Jonathan Owens, Simone Biles's Fiancé and NFL Player?
"The easiest yes!" Simone wrote about the couple's engagement.
By The Editors
'Too Hot to Handle' Season 3 Was Filmed in Actual Paradise
A.k.a. Turks and Caicos.
By Jenny Hollander
The Best Celebrity 'Squid Game' Costumes
A handful of stars chose this year's most popular theme.
By Quinci LeGardye
The ‘Lizzie McGuire’ Cast Then & Now
'Lizzie McGuire' is getting a modern reboot. In honor of the Disney Channel classic's highly-anticipated update, here's a look at the cast then and now.
By Kayleigh Roberts
A Clip of Harry and Meghan Was Reportedly Booed at a British Awards Show
The video was from the couple's interview with Oprah.
By Marie Claire Editors
“We’re in a time in which we’re no longer settling for reform, but genuine reimagination.”
By Lola Ogunnaike