Happy Valley and Killing Eve stars join BBC's long-running detective drama

As usual, the guest cast for the new season features some big names from the entertainment industry, including Miranda star Sarah Hadland, Killing Eve's Sean Delaney and Steffan Rhodri, best known for playing Dave Coaches in Gavin & Stacey.

Also joining the guest cast is Happy Valley's Siobhan Finneran, who also happens to be in a relationship with the show's main star, Don. 

The two actors met on the set of ITV crime drama The Loch. Speaking about their relationship to The Times, Siobhan said: "We are both off the telly. Other than that we're pretty normal. You wouldn't think we were a power couple this morning, both running around trying to get out of the house on time. Hopeless."

They're joined by Scarlett Alice Johnson, who played Vicki Fowler in EastEnders, Ghosts star Ben Willbond and West End actor Gary Wilmot.

Rounding out the guest cast are Cold Feet actress Hermione Norris and Green Wing's Julian Rhind-Tutt.

Picking up after the events of the feature-length Christmas special, which saw Mervin waiting to hear from his newly discovered half-brother Sol, the new season follows the detective as he adjusts to life in Saint Marie, alongside the return of commissioner Selwyn Patterson.

The BBC's synopsis reads: "Selwyn's return to Saint Marie is disrupted by a suspicious death at Government House, where a man has fallen from the roof. It looks like a suicide, but DI Mervin Wilson suspects foul play. 

"However, no one was on the roof with the victim when he fell, and he had locked the roof door behind him. So, if this man was pushed, how did it happen?

"Meanwhile, Mervin is anxious to finally meet his half-brother Solomon, the other son of the mother Mervin never knew. Granted, the pair have never met before, but family's family! Surely, they'll get on like a house on fire?"

Alongside the new guest stars, several familiar faces will return, including Don Gilet as DI Mervin Wilson.

Don Warrington reprises his role as Commissioner Selwyn Patterson, after fans were left speculating whether he would be leaving the show for good.

Elizabeth Bourgine returns as Catherine Bordey, while Shaquille Ali-Yebuah appears as Officer Sebastian Rose and Shantol Jackson plays DS Naomi Thomas.

The team will also be joined by Catherine Garton as Mattie Fletcher, a new sergeant working under Mervin and Naomi.