A number of the team, including co-creators Steven Moffat and Mark Gatiss, Amanda Abbington (who plays Mary Morstan) and producer Sue Vertue, will pop by at the show's panel, reported Digital Spy.
The event is taking place on Saturday, October 24.
It will give attendees the opportunity to hear more about the upcoming Victorian special, which will air at Christmas time.
A fourth full series consisting of three episodes will begin filming in 2016.