Michelle Williams is reportedly engaged to Andrew Youmans.
The 37-year-old actress - who has 12-year-old daughter Matilda with her late former fiance Heath Ledger - has been quietly dating the financial consultant for several months, and it has now been claimed the pair are planning to marry.
A source told Us Weekly magazine: "She wants a good guy and a stable family life."
Michelle - who has also dated the likes of director Spike Jonze, actor Jason Segel and author Jonathan Safran Foer - was initially reluctant to get back into a serious relationship following the tragic passing of Heath from an accidental overdose almost 10 years ago.
A source said: "Michelle was totally focused on giving Matilda the best upbringing possible.
"It took her a long time to get over Heath."
The 'Manchester By the Sea' star had sparked she could be due to marry after she was spotted wearing a heart-shaped diamond ring at the Golden Globes earlier this month, but she insisted the accessory was simply a piece of "beautiful jewellery".
Michelle and Andrew have never been officially photographed together, but romance rumours began in July 2017, when they were spotted together in Rome, Italy, where she was filming 'All the Money in the World'.
Meanwhile, the actress recently admitted she felt a "sadness" when she thought 'All the Money in the World' would have to be pulled following sexual misconduct allegations made against Kevin Spacey, who played J. Paul Getty, one of the main characters in the thriller.
But director Sir Ridley Scott replaced him with Christopher Plummer just weeks before the movie was due to be released, and Michelle has praised the filmmaker for his quick thinking.
She said: "We went through a lot with the film and we realised that this film that we loved and that we loved working on together was gonna basically be for nought.
"And there was some sadness around that, more sadness around the allegations and the pain that's been caused, and then this phone call came, this late breaking idea of how to save the film, rewrite the story, do the right thing, and I was exuberantly immediately on board."