Armie Hammer's marriage was reportedly sent into a "downward spiral" after his wife discovered texts from Lily James on his phone.
According to a source, his marriage ended after his wife Elizabeth Chambers found passionate messages on his phone in 2019 from a mystery woman who called herself "Adeline".
Adeline was reportedly the name James used on her call sheets and on her trailer while filming Rebecca with Hammer.
The source told The Daily Mail that James was also spotted flirting with her on-screen husband Hammer, who has two children with Chambers.
"She was not subtle. And he was into it, no doubt about it. She was touching him constantly, giving him long, smouldering looks," the source said.
After Chambers reportedly found the texts, she was "devastated and heartbroken."
But according to the Daily Mail, she tried to repair her 10-year marriage, and she and Hammer went to couples therapy and had plans to renew their vows - until Chambers received a sexually explicit text from Hammer that she "knew wasn't meant for her".
The reports come after photos emerged last week of James kissing another married co-star, Dominic West.
The Mamma Mia: Here We Go Again star was pictured with West during a trip to Rome, sparking rumours of West's infidelity to his wife.
In a bizarre display of unity a day after the story broke, West and his wife Catherine Fitzgerald kissed for photographers outside their house and gave the media a note which read: "Our marriage is strong and we're very much still together."