Did You Notice This Awkward Mistake During the New Year's Day Episode of 'Sherlock'?

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.

Follow Marie Claire on F (opens in new tab)acebook (opens in new tab) for the latest celeb news, beauty tips, fascinating reads, livestream video, and more.