Shetland's Alison O'Donnell has expressed her delight at co-star Lewis Howden stepping into a more prominent role in the upcoming series, calling him as an "untapped resource".

Lewis, who made his first appearance as Sergeant Billy McCabe in the inaugural series of the popular BBC crime drama, which is set in Shetland, is set to take on a larger role in the forthcoming 10th season.

In the new episodes, he is involved as the officers are looking into the death of a woman who his wife Morag used to work with.

Alison, who portrays Detective Inspector Alison "Tosh" McIntosh in the show, said it was high time for this development and that the entire team was thrilled about it, reports theDaily Record.

She said: "Having Lewis come to the fore was nothing but a pleasure.

"He has won over the hearts of our audience with his nuanced performance, his steady hand and stylish beard."

She continued: "It was time! He has been an untapped resource for so long and he is such an exceptional actor so we were all really excited, me especially as we had so many great scenes together."

Lewis typically films his scenes in a Glasgow studio, but this season he joined the rest of the cast on location in the Shetland Islands for the first time since a single scene in the fourth series.

Alison revealed: "He loved coming up to Shetland with all of us and having some new costumes to wear!"

The upcoming series of Shetland will follow Tosh and Detective Inspector Ruth Calder (Ashley Jensen) as they investigate the killing of retired social worker Eadie Tulloch in the isolated village of Lunniswick.

The duo believe locals are concealing information about their connections to the elderly victim, as a complex web of deception begins to unravel.

A synopsis reveals that whilst the detectives delve deeper into the tight-knit community, "shocking, long-buried secrets rise to the surface with unexpected consequences for all - including the team".

Shetland started in 2013 and so far nine series of the gripping murder mystery drama have aired.

Shetland returns on BBC One and BBC iPlayer from 9pm on Wednesday November 5.