The image (above) features Suranne and Shaun in character as DCI Amy Silver and Chief Petty Officer Elliot Glover and was taken earlier this year before production was paused due to the pandemic.
Filming resumed on the six-part series earlier this week near Glasgow.
The BBC has also announced new casting including Stephen Dillane (Game Of Thrones), Lolita Chakrabarti (Riviera), Daniel Portman (Game Of Thrones), Lorne MacFadyen (Grantchester), Stephen McCole (Save Me), Tom Gill (Peterloo), Lois Chimimba (Top Boy), Anita Vettesse (The Loch), Bobby Rainsbury (Call The Midwife), Cristian Ortega (Beats) and Lauren Lyle (Outlander).
They join the previously announced cast which includes Anjli Mohindra, Martin Compston, Paterson Joseph, Connor Swindells, Adam James, and Gary Lewis.
A teaser for the show reveals: "The mysterious disappearance of a Scottish fishing trawler and a death on-board a Trident nuclear submarine bring the police into conflict with the Navy and British security services.
"DCI Amy Silva leads an investigation on land and at sea into a conspiracy that threatens the very heart of Britain’s nuclear deterrent."
The six-part fictional drama series will be set and filmed in Scotland.
It will air in the UK on BBC One.