The Broadway performer shot to fame without a safety net in The Greatest Showman. The resulting public scrutiny was painful, she says, but it was the ideal grounding to step into the shoes of presidential widow Mary Lincoln

Bathed in the fluorescent glow of a rehearsal studio on the south bank of the Thames, Keala Settle is embodying a woman redefining herself in the court of public opinion. Cast as former first lady Mary Lincoln in Mrs President, a sombre and haunting stage production that begins a six-week run at London’s Charing Cross theatre this month, she grapples with the turbulent inner world of Abraham Lincoln’s wife, vilified by the media and eager to rewrite herself in the eyes of the US after her husband’s assassination and the civil war.

As an actor, and woman, Settle – known globally for her performance in The Greatest Showman as bearded lady Lettie Lutz – is also done with being what people tell her to be. It has, she explains, taken 10 years to reach this point. But her own encounters with celebrity and grief were the ideal preparation for this psychological drama. “This role – I jumped at it. I’ve never related to anything so closely.”