Emma Heming Willis, the wife of retired US actor Bruce Willis, has spoken for the first time publicly about how his brain "is failing him" now and his "language is going".

The Sixth Sense and Die Hard star, 70, was diagnosed with frontotemporal dementia more than three years ago.

"Bruce is still very mobile. Bruce is in really great health overall, you know," she told ABC News via Good Morning America on Tuesday. "It's just his brain that is failing him."

The author of an upcoming book about her family's experience with dementia, Heming Willis also advocated for fellow carers. "The language is going, and, you know, we've learned to adapt," she added.

"And we have a way of communicating with him, which is just a... different way."

The Willis family revealed in 2023 that the star had been diagnosed with frontotemporal dementia, which, according to the NHS website, is "an uncommon type of dementia that causes problems with behaviour and language."

A lesser-known but deeply impactful condition, it is estimated by Alzheimer's Research UK to affect more than 30,000 people around the country.

Model and entrepreneur Heming Willis said she thought at first she had to help her husband all by herself, which led to sleepless nights and withdrawal from social life.

She said she hopes her new book, titled Unexpected Journey: Finding Strength, Hope, and Yourself on the Caregiving Path, can serve as a road map and guide for other carers whose lives may be similarly affected by dementia.

'Twinkle in his eye'

The family - including the couple's two young daughters, and Bruce's other three daughters with former partner, actress Demi Moore - still see flashes of his true personality, Heming Willis noted, as well as the "twinkle in his eye."

"Not days, but we get moments," she said. "It's his laugh, right? He has such a hearty laugh. And sometimes you'll see that twinkle in his eye, or that smirk, and I just get transported."

She continued, "And it's just hard to see, because as quickly as those moments appear, then it goes. It's hard. But I'm grateful. I'm grateful that my husband is still very much here."

Samantha Benham-Hermetz, executive director at Alzheimer's Research UK, told BBC News it was "heartbreaking to hear the impact" dementia was having on the "iconic actor" and his family.

She described Heming Willis's decision to speak publicly about her husband's diagnosis as "a powerful act of courage", saying her words will "resonate with so many people affected by dementia.

"Her openness will mean so much to the many families who are facing similar challenges, reminding them that they are not alone," she added. "Personal stories like Emma and Bruce's are vital. They raise awareness, foster understanding, and highlight the urgent need for research."

Heming Willis was speaking in a preview of ABC's special, Emma & Bruce Willis: The Unexpected Journey, which airs in the US on Tuesday at 20:00 BST. It will be made available to stream the following day on Disney+ and Hulu.