'We've made something very complete': Benedict Cumberbatch hints new Sherlock series may be the last after revealing it will be 'hard to follow on' from the new episodes

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It is one of the most popular TV shows on British television.

But Benedict Cumberbatch hinted that the fourth series of Sherlock, which debuts on New Year's Day, could be the last, despite its huge success.

The actor, 40, revealed to Weekend that while the cast 'never say never' on the show, the upcoming series features a story line that could be difficult to follow on from.

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Say it isn't so! Benedict Cumberbatch hinted that the fourth series of Sherlock, which debuts on New Year's Day, could be the last, despite its huge success

The BBC show has found huge success since it first premiered in 2010 - with it now being streamed in more than 180 territories and the third series becoming the UK's most watched drama of all time.

However Benedict, who plays detective Sherlock Holmes himself, admitted to the New Year edition of the magazine that the fourth season could easily be the last. 

He explained: 'This new series goes to a place where it will be hard to follow on immediately.

Fourth and final: He explained to Weekend magazine: 'This new series goes to a place where it will be hard to follow on immediately' and that the new series is 'complete as it is'

'We never say never on the show, but in the immediate future we all have things we want to crack on with, and we've made something very complete as it its.

Before he added: 'So I think we'll just have to wait and see.' 

A three-part series of the hit show kicks off once again on Sunday for the first time since January 2014 - after a New Year's one-off special last year.  

Alongside co-star Martin Freeman as Watson, the series begins with an episode called The Six Thatchers - which sees a twist on Arthur Conan Doyle's classic Holmes tale The Adventure Of The Six Napoleons.

It's back: A three-part series of the hit show kicks off once again on Sunday for the first time since January 2014

It begins with a case that's been baffling DI Lestrade, played by Rupert Graves, and his colleagues at New Scotland Yard, revolving around a tragic young man who had seemingly managed to be in two places at the same time. 

However, the teaser trailer for the new series released last week focused not on the crime, but the characters' personal lives instead - with sidekick Watson welcoming his first child with Mary Morstan, played by Amanda Abbington.

In the new trailer the couple are seen cradling their child lovingly, before they embark on the newborn's christening alongside close friends and family. 

Moving on: However, the trailer released last week focused on the characters' personal lives instead - as Watson welcomes his first child with Mary Morstan (L)

Never without wit however Benedict, who's character is famously uninterested in family and love, admits after the emotional footage: 'Sherlock has always been very protective of them as a family' - before the trailer cuts to the detective fluffing his words during his speech at the celebration.

However Benedict himself admitted to the magazine that the new series sees a different, less arrogant side to Sherlock because of the baby. 

'He's let care in to his life,' he explained. 'He cares about John Watson and his wife Mary, and the newborn daughter Rosamund Mary they introduce in the first episode.

Besotted: In the new trailer the couple are seen cradling their child lovingly, before they embark on the newborn's christening alongside close friends and family

The British star continued: 'Sherlock feels very protective towards the three of them, even though he's not a natural when it comes to babies,' before he joked: 'I hope my skills and interaction with my own child are more engaged than his are!' 

Benedict and his wife Sophie welcomed their son Christopher in June last year, and are expecting their second child in spring 2017. 

While he ackowledges that Sherlock is far different in his approach to kids than himself, Benedict further admitted that the character's distancing from Watson's daughter stems from a good place.

He said: 'Sherlock's seemingly indifferent to the child, which is comic at times, but it's all underpinned with a deep love. He's a guardian angel, really.'

The new episode of Sherlock premieres on BBC One on January 1st 2017 

Bigger things: Benedict will no doubt be kept busy if the series does end, as he is expecting his second child with wife Sophie Hunter (L) in spring 2017