Written by Stephen Thompson, ‘The Sign Of Three’ will air at 8.30pm on Sunday 5 January on BBC One.

> Find out all the details on Series 3 so far in our summary.

Watch the trailer…

The official synopsis reads: “Sherlock faces his biggest challenge of all – delivering a Best Man’s speech on John’s wedding day! But all isn’t quite as it seems. Mortal danger stalks the reception – and someone might not make it to the happy couple’s first dance. Sherlock must thank the bridesmaids, solve the case and stop a killer!”

> Order Series 3 on DVD on Amazon.

> Buy the Series 1-2 boxset on Amazon.

Are you looking forward to ‘The Sign Of Three’? Let us know below…