Hirsute actor Martin Compston has told of the effort he put in to master the look that has won him millions of fans.
The Scottish star has starred as DI Steve Arnott since Line of Duty's launch in 2012 - with viewers stunned at his changing appearance over the years.
BBC iPlayer's official Instagram account got all nostalgic, posting a series of photos from each of the six seasons, with 36-year-old Martin's character going from baby faced to a full beard.
The Daily Record tells how the Greenock-born actor reposted the photos to his Instagram stories, writing: "Ten year to grow a beard".
And Steve Arnott's 'glow up' over the years was also the talk of messageboards as fans around the world had their say.
The hugely successful BBC cop drama came to an end last week, with 12.8milion people tuning in to watch season six finale's controversial ending to the long-running "H" storyline.
One wrote: "Steve's facial hair!"
"Steve Arnott's beard needs it's own page..."
Another wrote: "Steve's glow up in series 5".
A fourth commented: "Taken Steve a decade to grow that beard!"
It comes after Martin revealed he and his co-stars are to get matching tattoos after the series finale earned more than 12 million viewers.
During Sunday night's episode of the BBC One series, DSU Ian Buckells, played by Nigel Boyle, was unmasked as the mysterious H, the corrupt police officer at the top of a criminal conspiracy.
The Scots actor took to social media on Monday to thank fans for 'sticking with us' despite the finale not being the "'urgent exit' type ending some anticipated".
He also revealed that he and his Line of Duty co-stars Adrian Dunbar, Vicky McClure and series creator Mercurio had agreed to get "AC12million" tattoos if the show hit the milestone.
He joked that it was an "inconceivable and ridiculous scenario".
In a message posted on Twitter, Compston thanked those who had reached out to him since the episode aired.
He wrote: "Hey folks now the madness is slightly dying down just want to thank everybody who reached out about last night and the series as a whole, we've truly been blown away by the reaction and love for the show we're proud of it.
"Fully understand it wasn't the 'urgent exit' type ending some anticipated but we appreciate you sticking with us.
"Felt many emotions from excitement and anxiety at the hype to relief that it's over.
"Now I just feel immense pride our show that started on Wednesday's on BBC2 has just smashed every overnight drama record since they began.
"Finally myself, Vicky, Adrian and Jed made an agreement in the inconceivable and ridiculous scenario we ever got twelve million viewers we would get 'AC12million' tattoos.
"We'll see who's good to their word......"
