Sherlock Season 4: 20 Easter Eggs & References In 'The Final Problem'
2. Paul Weller As A Viking
In this same scene, there is a very unlikely - and very easily-missed - cameo from a British rock star.
At one point, we see John inspecting the body of a man dressed as a Viking lying on the floor at Baker Street. Eagle-eyed music fans will note that this is Paul Weller of The Jam.
As for what he is in doing in Sherlock, Weller is a friend of self-confessed rock afficionado Martin Freeman. Freeman previously appeared in the video for Weller's Pick It Up, so it seems like this is Weller returning the favour.