Bruce Willis, who retired from acting last May due to aphasia, has been diagnosed with frontotemporal dementia (FTD), his family announced Thursday.

His wife, Emma Heming, ex-wife Demi Moore and daughters Rumer, Scout, Tallulah, Mabel and Evelyn – discovered that Willis' aphasia (speech disorder caused by damage to a specific area of ??the brain) had progressed to dementia.

"It's painful, but it's a relief to know that we finally have a clear diagnosis," the family said. “FTD is a cruel disease that many of us have never heard of and it can affect anyone. For people under 60, FTD is the most common form of dementia, and because it takes years to be diagnosed, FTD is likely to be much more common than we think.”

Dementia is not a specific disease, but rather a general term for the impaired ability to remember, think or make decisions that interferes with the performance of daily activities.

Bruce Willis, who started his career in "Moonlighting", was one of the action movie stars of the 1980s-1990s, known for the "Die Hard" franchise, as well as other roles in productions such as "Pulp Fiction", "The Fifth Element", "The Last Boy Scout", "Twelve Monkeys", "The Sixth Sense", "Looper" and "Moonrise Kingdom".