Actor Douglas Henshall has taken to twitter to warn fans of the hit BBC television series Shetland that the final episode is 'going to mess with them'.

The Glaswegian, who has starred in the show for four series, plays Detective Inspector Jimmy Perez, who is regularly tasked with solving crimes on the Island of Shetland. 

This series features the reopening of a murder investigation from 1994 which sees the convict Thomas Malone return to the island. When another girl is murdered just day's later the police are tasked with finding out if there is a connection between the two.

The sixth and final episode of series four is set to come to a dramatic close on Tuesday night after last week's episode left viewers questioning everything with a shocking twist in the final minutes.

To confuse viewers further, Dougie posted a cryptic tweet on Friday about the finale, which said: "It’s Friday night. The final episode of this seasons Shetland is up on Tuesday and I just want to give you a heads up.

"It’s going to mess with you a little (a lot) so be around people you like. #Shetland."

The post has been flooded with comments praising the programme's originality and beautiful setting. 

One fan @Jemimaquack wrote: "Such beautiful scenery too. I do watch a fair amount of TV but Shetland is one of my favourites."

Another @susanalou asked: "If we live alone are we going to need to invite people over or will a cushion to hide behind and some booze do the trick ?"

To which Dougie replied: "Whatever softens the blow."

The final episode will be aired on BBC One Scotland at 9pm, Tuesday March 20.