According to his family, actor Bruce Willis has frontotemporal dementia.
They claimed it was a “relief to finally have a precise diagnosis” in a statement posted on social media.
The 67-year-old was given a more precise diagnosis after progressing from his initial aphasia diagnosis, which results in speech impairments, made in the spring of last year, according to the family.
They gave their “sincere thanks for the overwhelming outpouring of love.”
Frontotemporal dementia is the most prevalent type of dementia in adults under 60, the family continued.
“Today there are no treatments for the disease, a reality that we hope can change in the years ahead,” the statement said.
Willis became a household name in the 1980s and 90s after starring in blockbuster films such as Die Hard, The Sixth Sense, Armageddon and Pulp Fiction.
He has also been nominated for five Golden Globes – winning one for Moonlighting – and also three Emmys, where he won two.
But his family said last year that Willis would give up acting, as his aphasia as it was affecting his cognitive abilities.
The new statement on Thursday said they hoped media attention would raise awareness of the actor’s condition.
It said: “Bruce always believed in using his voice in the world to help others and to raise awareness about important issues both publicly and privately.
“We know in our hearts that – if he could today – he would want to respond by bringing global attention and a connectedness with those who are also dealing with this debilitating disease and how it impacts so many individuals and their families.”
Family members of Willis, including his wife Emma Heming and their two daughters as well as his ex-wife Demi Moore and their three daughters, signed the declaration.
Frontotemporal dementia is a “uncommon” form of the disease that affects behavior and language, according to the UK NHS website.
Other symptoms include muscle weakness, sluggish or stiff movements, loss of bladder or bowel control (although this usually occurs later), and slow or stiff breathing.