Robson Green was spotted outside a local pub and locals think they know what was being filmed.

The Old Palace in Langley Hill, Kings Langley, became 'The Hope and Anchor' as film crews were at work inside and outside the boozer.

The actor has appeared across many British TV favourites but, as he is sporting a slightly dated suit in some pictures taken outside the pub, it appears Grantchester was the programme being shot.

Watford Observer: Filming outside The Old PalaceFilming outside The Old Palace (Image: Jo Kedgley)

Grantchester initially followed vicar Sidney Chambers, played by James Norton, as he found himself investigating mysterious wrongdoings with the help of Detective Inspector Geordie Keating, played by Green.

Chambers was then replaced by Tom Brittney’s vicar Will Davenport but Green remained a key cast member.

There have been eight series broadcast so far, with a ninth announced last month. The upcoming series will be Brittney's last.

Watford Observer: Filming outside The Old PalaceFilming outside The Old Palace (Image: Contribution)

Hollyoaks actor Rishi Nair will be taking over the lead role, as vicar Alphy Kotteram.

The Old Palace’s signs were replaced with signs for The Hope and Anchor during filming.

Update: ITV has confirmed Grantchester was being filmed at the pub

Watford Observer: Filming outside The Old PalaceFilming outside The Old Palace (Image: Jo Kedgley)

Watford Observer: 1706983017069830 (Image: Jo Kedgley)

Watford Observer: Filming outside The Old PalaceFilming outside The Old Palace (Image: Contribution)

Watford Observer: Filming outside The Old PalaceFilming outside The Old Palace (Image: Jo Kedgley)

Watford Observer: Filming outside The Old PalaceFilming outside The Old Palace (Image: Jo Kedgley)

Watford Observer: Filming outside The Old PalaceFilming outside The Old Palace (Image: Jo Kedgley)