Dominic West and Lily James reportedly grew close after being forced into a bubble together while filming their new drama The Pursuit Of Love.
The married actor, 50, was pictured kissing and cuddling his co-star, 31, on a trip to Italy over the weekend.
He was seen stroking Lily’s hair and nuzzling her neck over an intimate lunch in Rome on Sunday, but has since insisted his marriage to wife of 10 years, Catherine Fitzgerald, is still “strong”.
Dominic and Lily have known each other for years after starring in a stage production of Othello together back in 2011, but a new report suggests the pair grew closer over the summer while they were shooting their latest project.
They began filming a three-part adaptation of Nancy Mitford’s novel for the BBC back in July on location around Bristol and Bath.
The Mail Online reports the pair would have been forced to go into a bubble together and separated from their friends and family for weeks on end.
A source told the site: “When you are making films these days, you end up locked down in a bubble for 12 weeks.
“People go crazy. You aren’t allowed to hang out with people from outside the bubble, so you end up spending time with each other.”
Another explained: “Actors have to sign Covid contracts these days, which mean they promise they will stay in that bubble throughout filming.
“They can’t see their families even at weekends. It means that people are thrown together in a very intense way.”
The shoot wrapped in early October, and Lily posted a sweet tribute to her castmates on Instagram.
She wrote: “I feel so so proud and grateful and lucky to have got to spend these long/short weeks with you [all]… and our whole wondrous cast and crew.
“I cannot get enough of you!! I’m so full of you and the story and life. Life-affirming.
“During the strangest most difficult times. I’m nostalgic already. Must stop typing. Heavy bright heart. #thepursuitoflove.”
Lily and Dominic first worked together back in 2011 in a production of Othello at the Crucible theatre in Sheffield.
Lily was just 22 when she played Desdemona opposite Dominic, then 41, as the pot-stirring Iago.
After pictures of their cosy outing in Italy were published this week, Dominic put on a united front with his wife outside their home in Wiltshire.
They were pictured kissing and held up a note which declared their marriage is still “strong” and they are still “very much” together.
The couple are now said to have fled the UK and flown to Ireland to hole up in Catherine’s ancestral home – the 15-bedroom Glin Castle.
Lily is single after splitting from her boyfriend of five years, Matt Smith, last week.