Happy Valley fans make startling observation about Sarah Lancashire's ... trends now

Happy Valley fans have made a starling observation after seeing a throwback picture of the series' leading lady Sarah Lancashire. 

The actress, 58, plays Sergeant Catherine Cawood in the hugely-popular police drama which is in its gripping third and final season.

After Sunday night's episode the Twitter page @QueenLancashire shared a photo of BAFTA award-winning actress Sarah with the ABBA tribute band Swede Dreamz. 

Fans will recall that Catherine and her colleagues Ann and Joyce went to see the band in series two after Ann joined the police following her kidnap and rape ordeal. 

Sharing a pic of Catherine at the concert, one viewer said: 'Throwback to when ABBA met Catherine (Sarah)'.

After looking at the photo, one eagle-eyed fan said: 'That picture looks like Sarah dressed as Catherine, not Catherine, it's MAD how her physicality creates the character.'

Another said: : '1000%! Never thought of this. It's so obviously Sarah in Catherine's clothes. Probably the great big beam on her face too. (We rarely get that from our Cath these days haha).' 

A third then commented: 'That's a really good observation. Spot on!'

It comes as it was revealed that Happy Valley has filmed extra scenes in a bid to keep the hugely anticipated finale to the BBC drama underwraps.

Star of the third and final series of the crime series Amit Shah, who plays the drug -dealing pharmacist at the centre of this season's murder plot, has spilled the show secrets.

Speaking on the podcast Obsessed with... Happy Valley, Amit insisted he has no clue how his character Faisal's storyline will end as he filmed multiple endings.

'I still don't know how it all ends up for him because we filmed the final scenes in various different ways,' he explained.

Viewers have seen Faisal murder Joanna Hepworth in a fit of rage after his drug-dealing sideline began to unravel.