Although return date for Benedict Cumberbatch's sleuth still not announced...

A teaser trailer for Sherlock series three has been unveiled – scroll down to the bottom of the page and click to watch.

The clip, which was first aired on BBC One last night (August 2) after a re-run of the final episode of Series Two, The Reichenbach Fall, is only 25 seconds long and doesn’t reveal how Benedict Cumberbatch’s sleuth was able to fake his own death.

However, a shadowy version of Holmes is shown in shots of other characters including Rupert Graves’ DI Lestrade, Una Stubbs’ Mrs Hudson and Martin Freeman’s Doctor John Watson, who is now sporting a moustache.

It was revealed last week (July 30) that Danish actor Lars Mikkelsen has been cast as the villain in the new series of the show. Fans have speculated that Mikkelsen, who previously starred in The Killing as mayoral candidate Troels Hartmann, will play a character based on Charles Augustus Milverton, a character known as the “king of the blackmailers” from one of Sir Arthur Conan Doyle’s classic short stories. However, no official details have been revealed.

Sherlock‘s return date has yet to be announced, but it is expected to air on BBC One later this year (2013).