The three-episode fourth season of the "Sherlock" series which aired this January might be the last. In a recent interview, series actor and co-creator Mark Gatiss revealed "Sherlock" season 5 might get canceled. The primary reason would be the lead actors' busy schedule.

"I honestly don't know if there will be any more. It's incredibly difficult to get Benedict [Cumberbatch] and Martin's [Freeman] diaries to align," Gatiss teased speaking on awards night according to The Sun. He added that "Sherlock" season 4 had a happy, satisfying ending and it's the type of ending which he would be happy even if they left it that way.

The last episode of the fourth season aired on January 15. In a previous report, fans got some hints that there would be no more season 5 through Benedict himself. However, the production dismissed it as a misinterpretation of the actor's statements.

Meanwhile, co-creator Steve Moffat also cast some doubts of the series' return. According to a report, Moffat said in a separate interview that the recent installment might likely be the last but he is hoping it could still continue.

Gatiss also stated that the last day of filming ended oddly. "The last day tends to be an odd day-it's never quite as you imagine it," he said. He explained that they tried to schedule it so the last shot will be Sherlock and Watson running out of the building. However, they forgot one last shot of Watson falling over. "So that's how it ended. As usual, these things end with a whimper," he added.

Some insiders also revealed the rather frosty friendship of the series' iconic pair. It looks like Sherlock and Watson are not as friendly behind the camera. "Benedict and Martin aren't mates and they don't spend time together away from the show," a source said. The insider added that the two have a very professional relationship but there is no warmth that one would expect in colleagues that have been working together for several years and the desire to return for "Sherlock" season 5 is not there.