But behind the scenes, she was quietly coping with a very serious family crisis.
At the end of 2016, around the time The Crown was first released, her husband, Stephen Campbell Moore, fell ill. A benign tumour was discovered on his pituitary gland at the base of the brain, which controls metabolism.
The Crown’s filming schedule continued, however, and though the 33-year-old gave a flawless performance as the reigning British monarch for the second season, she privately dealt with the possibility she may soon be a widow and single mother to the couple’s young daughter.
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Moore, who Foy met on the set of 2011 film Season of the Witch, underwent surgery to remove the tumour.
“You realise you’re not the most important person in that process, and everybody who loves you goes through far worse,” the 38-year-old actor told The Sun.
“My daughter didn’t know what was going on at all. But my family did, and I could see it in them.”
Moore said that he had to prepare for the worst as he went in for surgery each time.