LINE Of Duty viewers have been transfixed by the traditional guessing game of 'guess the wrong'un' each time the BBC drama airs.
But many have also been busy spotting where they have seen the parade of dodgy cops, crims and slippery lawyers.
Here we attempt to help out with the latest round of 'where have I seen them before?'
Because from EastEnders to Bridgerton and even The Inbetweeners, Line of Duty's big stars have always been hiding in plain sight...
DCI Ian Buckells
He got banged up in jail for being dodgy, but Nigel Boyle's character was no less of a law-breaker when he was The Inbetweeners' barman.
As the rogue pint-puller he served a whole pub packed with schoolchildren and only twigged that was the case after a row with Will McKenzie in the classic sitcom.
Jimmy Lakewell
As the drama's criminal lawyer Jimmy wound up in prison, where he met a grisly end after Steve Arnott sprung him from jail.
But viewers will also know him as Neil Godwin, manager of The Office's Swindon branch who becomes David Brent's boss - and then ultimately sends him packing.
PCC Rohan Sindwhani
Political overlord Rohan Sindwhani looked like he was making life very difficult for Ted Hastings but may very well have been his protector (as usual with Line of Duty, playing 'pick the baddies' is an inexact science).
He is played by former EastEnders star Ace Bhatti, who was Zainab's brutally abusive ex-husband - and also played Emmerdale's Bobby Khan.
Supt Ted Hastings
Ted Hastings can spot a wrong'un at twenty paces but actor Adrian Dunbar has also played murder suspects and even - mother of God - a corrupt cop himself.
The actor, 62, starred in BBC hit Ashes To Ashes as Detective Inspector Martin Summers, a corrupt PC from Fenchurch East police station.
Come on now, fella.
DI Kate Fleming
Vicky McClure is one of the best things in Line Of Duty as no-nonsense DCI Kate Fleming.
But the 37-year-old actress was on far wilder form in her breakout role in the This is England film in 2006 and the Channel 4 TV series that followed, as Lol.
DCI Jo Davidson
She certainly seems to be firmly on the 'dodgy' list but AC-12 still haven't managed to pin enough dirt on Davidson to bring her in (yet).
Kelly McDonald, the actress who plays her, has starred in everything from Nanny McPhee to Boardwalk Empire and Harry Potter.
But she is still perhaps best-known for appearing in 1996 cult classic Trainspotting as Diane, a ruthless schoolgirl who blackmails Renton.
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DC Jodie Taylor
There is something of a revolving door between Line of Duty and Bridgerton, with no fewer than five stars appearing in both.
The most notable is Claudia Jesse, who plays both sass merchant Eloise Bridgerton and series-four sneak Jodie, who reported Kate's activities to Roz Huntley.
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DI Steve Arnott
Martin Compston puts on an English accent in Line Of Duty but he is of course comes from Greenock in Scotland.
Before becoming familiar to viewers as Steve Arnott, the 36-year-old actor played Ewan Brodie in BBC drama Monarch of the Glen.