Line of Duty fans are just days away from finding out who H really is it seems, in the much anticipated finale of series six.
An action-packed new trailer teased that the moment we'd all been waiting for was upon us, and that the truth would be disclosed in the seventh episode of the series.
Amid fears it could be the final ever episode of the BBC crime drama, the trailer suggested AC-12 and the nation would finally know the identity of the fourth member of 'H'.
The teaser suggested all past investigations have led to this huge episode, and viewers are guessing galore over who H really is - amid predictions a major twist will air.
In series five, viewers got the bombshell that H could actually be four people, rather than one shady individual bent copper.
Those who have already been identified are Dot Cottan, Derek Hilton and Senior Legal Counsel Gill Biggeloe, leaving us with one final name to discover.
Line of Duty writers have been dropping endless clues to keep us guessing ever since, with fears one of AC-12 could be the mystery bent copper - while viewers will hopefully find out on Sunday evening.
But until then, let's take a look at the prime suspects and theories as to who will be unveiled...
Chief Constable Philip Osborne
Someone quickly leading the polls to be revealed as 'H' is someone right at the top.
Philip Osborne takes centre stage in the new trailer dropped by the BBC, as Hastings mentions looking for the mystery corrupt officer.
Suspicions have risen following the known information that over the years, Osborne has worked with Marcus Thurwell and Ian Buckells - both of whom have been considered dodgy.
Let's not forget Osborne's involvement in series one, after the botched anti-terror raid which led to the death of an innocent man.
He urged the officers involved including Steve Arnott to lie about what really happened.
Since then he has criticised Hastings and AC-12, and even planned the overhaul of AC-12 and it's merge with AC-3 - cue Patricia Carmichael's return.
One fan said of the trailer: "It’s the f***ing Chief Inspector I’m telling you."
Another added: "My money for 'H' is on Chief Constable Philip Osborne. He's essentially the villain from the first ever episode and the very reason Steve Arnott winds up in AC-12 and kicks off the events of the show! They've nicked a couple of ACC's so now its the biggest fish of all."
Kate Fleming
AC-12's finest Kate Fleming has concerned loyal fans she could be the corrupt officer, especially with her no longer being in her original team.
Now, the trailer has hinted at this despite her appearing to be cracking the case and on the good side of the law - with fans spotting clues in the new scenes yet to air.
One viewer wrote: "Just realised that on the #LineofDuty trailer for the final episode, the same character appears on the word "H" and the fourth dash of the audio morse code. Red herring or secret reveal?"
This is correct too, with Kate appearing just as Hastings says 'H', and on the fourth ring of the famous theme tune.
Not only that but Kate also appears again amongst other H suspects in a montage, just as Ted shares his plan to track down the final member of infamous group.
Marcus Thurwell
There is much confusion after the shortest appearance of a character in the show's history.
While he was mentioned to be in a mystery location in series three, it wasn't until series six episode five that we finally saw who retired cop Marcus Thurwell was.
He very quickly became a 'H' suspect over his past actions, but a twist in episode six saw the news that he was dead - with his corpse seemingly found in Spain where he was living.
But a video left many convinced he'd actually faked his own death, and was still out there - so there's still potential for a 'H' twist yet!
After all, he does appear in the trailer when Hastings mentions looking for 'H', so could it be a red herring or is he definitely linked?
DCI Joanne Davidson appeared shaken when she was shown photos of Thurwell during her interrogation in episode five, so could he be the elusive 'H' and she's actually terrified of him?
DCI Patricia Carmichael
Ruthless character Carmichael has certainly won over the nation with her brutal one liners and quips at her colleagues.
But she also seems to be hiding something, amid her desperation to close the anti-corruption unit.
Earlier, speculation was strife when corrupt lawyer Jimmy Lakewell, who was murdered in prison, gave Steve Arnott more information about Gail Vella's murder, which Jo Davidson's unit has been investigating.
He told him to "look deeper into the race claim" and if you add "H" and "race claim" together and mix up the letters you can get "Carmichael".
Now, the trailer itself drops heavy hints she is corrupt too - from her appearing in a montage of characters when Hastings refers to 'H', to the fact she suddenly goes awol amid Ted, Kate and Steve's plan to get to 'H'.
Superintendent Ted Hastings
Of course, the trailer could be throwing us all off the scent, and perhaps someone is covering their tracks.
Poor Ted Hastings has been a prime suspect for the past two series, but to be fair his behaviour hasn't exactly cooled the rumours.
He was investigated in series five over the possibility he could be H, but was soon revealed to have been set up by official H member Gill.
That said there are several clues pointing to him being bent, despite him repeating every episode that his job is to find corrupt officers.
There's the money he paid to the widow of undercover officer John Corbett, murdered by the OCG after he tipped them off that there was a rat amongst them.
Never mind the fact his surname begins with the letter 'H', other clues have included his incorrect spelling of the word definitely, and a masonic handshake.
Line of Duty series six concludes on Sunday at 9pm on BBC One.
