Dame Joanna Lumley has said she has found the reaction to her Netflix series Fool Me Once “thrilling”.

The drama has been a juggernaut on the streaming service, topping the list of most-watched programmes.

The story is centred on a combat pilot (played by Michelle Keegan) in the military suffering from PTSD whose husband (Richard Armitage), from a wealthy family, is murdered.

Adapted from the novel of the same name by crime writer Harlan Coben, the show has gripped audiences with its twists.

Dame Joanna, who plays Armitage’s mother, the cold, upper crust matriarch, told the PA news agency: “It’s thrilling (the reaction) because you work away without any audience at all as you know whenever you’re filming and you’re just working with a crew and then it’s put together and it’s released.

She added: “I was rather taken aback when on New Year’s Day they told me that it would be released to 190 countries simultaneously.

Sujan Katuwal walking challenge
Dame Joanna Lumley with restaurant owner Sujan Katuwal (Ian West/PA)

“It’s extremely well-crafted and it’s got lots of twists and turns, lots of red herrings and people watching at home haven’t any idea what happens until the very last reel, that’s always good.”

Dame Joanna was speaking as she joined a restaurant owner as he began a charity challenge which will see him walk 3,000 miles through every London Borough.

Sujan Katuwal, who owns Panas Gurkha in Lewisham, south-east London, began his walk from the Embassy of Nepal, in west London, in support of Combat Stress, a charitable organisation dedicated to assisting Armed Forces and veterans coping with post-traumatic stress disorder (PTSD).