The air date for Sherlock season 3 has yet to be revealed for the UK, but the show's stars Benedict Cumberbatch (Sherlock Holmes) and Martin Freeman (Dr. Watson) may have already signed up for a fourth season of the popular detective series.

Sherlock creator Steven Moffat recently told Radio Times at the Cheltenham Literature Festival: "We had to inform the BBC that Martin and Benedict had commissioned a new series." Moffat continued: "They signed themselves up. They both announced that they were carrying on -- so that's good. Benedict, at some red carpet event somewhere, said he was carrying on forever. Martin, at another one, said, 'Yep, series four is happening.'"

The filming for Sherlock season 3 concluded Sept. 1, 2013, but the post-production stage continues. The air dates for BBC in UK and PBS in the US will not be announced until the post-production is completed. BBC recently stated that "Post-production will still be on-going for Sherlock until way into November," suggesting that the air date will not best until the end of this year or beginning of 2014.

Previous rumors pointed to a January 1, 2014 premiere air date but producer Sue Vertue tweeted back in August: "Not sure where #Sherlock latest rumoured tx date of 01/14 has come from. Not from me as tx date is not yet confirmed."

Other air date rumors started when blogger "Blogtor Who," who writes about TV shows including "Doctor Who," "Torchwood" and "The Sarah Jane Adventures," tweeted on Aug. 21: "Sherlock Series 3 Ep 1 is set in November and will air on Jan 1, 2014." The blogger insisted that Vertue did not actually deny the date of January 1.

It has been two years since the season 2 finale of the series ended with Sherlock Holmes faking his death, and the new title leaves fans wondering what happens to the detective. Episode 1 of Sherlock will be titled "The Empty Hearse."

"Sherlock" is a British television crime drama with a contemporary update to Sir Arthur Conan Doyle's Sherlock Holmes detective stories. The show was created by Steven Moffat and Mark Gatiss, and stars Benedict Cumberbatch as Sherlock Holmes and Martin Freeman as Doctor John Watson. Six episodes have been produced so far. The first three episodes aired in 2010, and series 2 aired in 2012. Production for series 3 started in March 2013.