Writer-producer Steven Moffat says Sherlock fans will notice a difference from the titular sleuth's usual abrupt demeanor in the contemporary show's upcoming, Victorian-era special.

Sherlock is a modern-day mystery-drama inspired by Arthur Conan Doyle's late 19th/early 20th century stories. The TV series stars Benedict Cumberbatch as Sherlock Holmes and Martin Freeman as his sidekick, Dr. John Watson.

The special edition of the program will -- for the first time -- give a nod to the time period of its literary roots. How or why it will take place more than a century earlier than the series normally does will not be explained in the episode.

"Sherlock is a little more polished," Entertainment Weekly quoted Moffat as saying Saturday at a Television Critic's Association press event. "He operates like a Victorian gentleman, instead of a posh, rude man. He's a lot less brattish."

Meanwhile, Freeman's Dr. Watson will be "more uptight," Moffat revealed.

No U.S. air date for the special has been announced yet.