BBC's hugely popular series "Sherlock" has made Benedict Cumberbatch and Martin Freeman huge stars and very much in demand in Hollywood. This demand seems to be delaying the filming and the premiere of "Sherlock" Season 4.

Mark Gatiss, co-creator of "Sherlock," said to Metro that "everyone wants to carry on doing Sherlock. It's a simple matter of schedules -- particularly Benedict and Martin."

The co-creator almost confirmed that "Sherlock" will return with a new season in 2016. "There was suddenly a kind of outraged response that it might not be back until 2016 but that's precisely how long it always is. It's always two years! But we'd like to return soon, of course," Gatiss said to Metro.

Cumberbatch's portrayal of Sherlock Holmes in the contemporary setting has elevated him to a super-star status. Gatiss sees this as fusing of the right man with the right part. Talking about Cumberbatch's sex appeal as Sherlock, Gatiss believes that it may have something to do with "the combination of the Byronic looks that Benedict has -- and the coat! -- that's made him into, possibly, the first sexy Sherlock Holmes."

Earlier, Gatiss' writing partner, Steven Moffat had said that they have already mapped-out the entire Season 4 and Season 5 of "Sherlock." Recently, he and Gatiss answered questions related to future seasons of "Sherlock" at an event organised by the Royal Television Society. Moffat said, as reported by The Hollywood Reporter (THR), that the plan will "get more detailed" as the production date nears.

Prof Moriarty is set to feature in "Sherlock" Season 4. According to THR's report, Moffat and Gatiss confirmed that Moriarty "would be featured in the new season." The co-writers said that "did you miss me" of Moriarty was not a last minute addition, but "they had long planned" this twist.

"Sherlock" fans may see new characters in the new season. Gatiss said that moving forward they intend to keep "Sherlock" new and introduce new characters. Also, the upcoming seasons will show Sherlock's "gradual humanization."

Talking about continuing the show beyond Season 5, Gatiss said, as quoted by THR, "The idea of growing older with it would be great. But it is hard to get everyone back together, because they have become extremely famous -- except for us."