That’s one of his Sarah Bernhardt posters so it’s actually a woman dressed as a man. Now that you mention it, I can see the Cumberbatch thing, though. Who would have guessed?
Lorenzaccio by Alphonse Mucha
Oooh, a Mucha boy.
oh okay well, I thought this was some Sherlock fan art. Hmm. Tumblr has RUINED me. Clearly.