Emily Mortimer says it was initially "freaky" filmingduring the pandemic, but that she felt "blessed" to have a job.
The three-part series, adapted from the 1945 novel by Nancy Mitford, was one of the first high-end TV drama productions to begin filming after the first lockdown.
Thestar — who wrote, directed, and acts in the series — said the production was a great distraction from Covid-19.
"It's had its pros and cons. It's been quite bonding. Initially, there was something exciting about being with a lot of people after not being with anyone for months on end.
"I felt genuinely blessed to have a job. There is something about this story being set between the wars, at a time when life was very fragile and everyone was living like there was no tomorrow. Our generation hasn't had that experience of life in such an intense way. I hope this cheers people up. It is about painful subjects but there's an energy to it."
Andrew Scott plays the wealthy and eccentric Lord Merlin in the BBC One period drama. He spoke of his excitement at returning to work and said the set felt extremely safe.
"Ironically I feel very safe on this set because you know everyone has been tested," he said.
"The crew did an incredible job; wearing masks all day and you have to make more of an effort as you can't read people's faces. Everyone was so thrilled to be back working. We were so lucky that we were one of the first back after the first lockdown."
- is produced by Open Book and Moonage Pictures for the BBC and is a co-production with Amazon Studios in the US, Canada, Australia, and New Zealand. It starts on BBC One on May 9.