Dominic West can be seen kissing Lily James in Italy on Sunday in bombshell pictures days before the actor insisted his marriage is still "very much together".
The Affair star, 50, was seen having an intimate lunch with Downton Abbey's Lily, 31, in Rome, and was pictured stroking her hair and nuzzling and kissing her neck.
In the snaps, the pair were also spotted messing around on a scooter, with Dominic wrapping his arms around Lily as they hopped on together.
The pictures were taken on Sunday - just two days before West put on a united front with his wife of 10 years, Catherine Fitzgerald, today.
West and his partner were pictured kissing and cuddling outside their Wiltshire home, with the actor telling The Sun the marriage is "still strong" and they are "very much still together".
The actor has been married to Catherine for 10 years and has four children with her.
Lily is newly-single after her on/off romance with Doctor Who star Matt Smith came to an end last week. She has yet to comment on the pictures.
A source previously told MailOnline Catherine was devastated by the pictures of her husband in Rome with Lily.
The insider said: "Catherine has seen the pictures and she's devastated. I came over to speak with her as soon as I knew about them.
"Catherine has been trying to speak with Dominic but he's not answering his phone. She's totally shocked because she didn't know anything was going on.
"They were very much together, so this is completely out of the blue.
"She thought they had a good marriage and now it's probably over. That's how she feels right now but the two of them need to speak but at the moment, she's lost for words."
However, during their photocall this morning, West declared: "I just want to say our marriage is strong and we are very much still together."
It comes as West' previous remarks about adultery have emerged, with the actor insisting husbands should not be kicked to the curb over extra-marital flings.
Speaking in 2016, he told the Evening Standard : "I mean, I think women should be more indulgent of affairs.
"I really do. It’s daft to kick someone out over a fling. Isn’t it? Everyone should turn a blind eye to men’s behaviour between the ages of 40 and 50. Let it all blow over."
West has also previously given his thoughts on monogamy in an interview with Harpers Bazaar magazine - calling it "not the necessarily natural way to be".
After starring in five seasons of The Affair - in which his character embarks on an extra-marital relationship - West was questioned why adultery makes such compelling drama.
He replied: "It’s one of those subjects that people have very strong opinions about because everybody is open to it and can experience it.
"It affects kings as much as it does snails. A lot of people have experienced it and a lot of people fear it.
"I suppose people suspect that the conventions that we have agreed upon in society...
"That a man and women can stay together for life or a certain amount of time without cheating...
"That they’re not really staying together based on anything other than how society thinks they should behave.
"It’s not the necessarily natural way to be, therefore there will always be adultery and intrigue about it."
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Dominic and Catherine dated at university and they married in Ireland in 2010.
They went on to have four kids together, daughter Dora, 13, son Senan, 12, son Francis, 11, and Christabel, seven.