Willis, 67, has starred in successful films including the Die Hard series, Pulp Fiction, Armageddon, Moonrise Kingdom, 12 Monkeys and Looper.
He has been nominated for numerous awards including five Golden Globe Awards, of which he won one, and three Primetime Emmys Awards, of which he won two.
In 2006, he was honored with a star on the Hollywood Walk of Fame in Los Angeles.
Revealing the news on social media, the Willis family said it was a “really difficult time” for them and thanked fans for their “continued love, sympathy and support”.
Aphasia is a disorder caused by damage to a specific area of the brain that controls language expression and comprehension, according to Johns Hopkins University School of Medicine.
This condition renders a person unable to communicate effectively with others, and Willis’ family said the aphasia was “affecting his cognitive abilities.”
The damage caused by aphasia may be caused by several things, including a stroke, head injury, brain tumor, infection, or dementia.
According to the NHS, the condition can affect people of all ages, although it is more common in people over 65 – when strokes and progressive neurological conditions are more likely.
The family did not give further details about Willis’ condition or its cause.
What are the symptoms of aphasia?
Aphasia can affect different people in different ways, although common symptoms involve difficulty with the main forms of communication; Reading, writing, speaking and listening.
Speaking problems are more noticeable and people with the condition may make mistakes in the words they use, according to the NHS.
This can manifest itself in using the wrong sounds in words, choosing the wrong word, or incorrectly grouping words into a sentence.
The NHS says that although aphasia affects a person’s ability to communicate, it does not affect their intelligence.
How is aphasia treated?
As with symptoms, treatment for aphasia varies from person to person.
Factors that influence treatment include the individual’s age, general health, medical history and the severity of the condition.
The most common practical treatment is speech and language therapy to help restore some ability to communicate, although it may also be necessary to develop alternative methods of communication.
According to the NHS, most people recover with some degree of aphasia, although this is more likely if it is caused by a one-time event such as a stroke.
Chances of recovery are lower if the aphasia is caused by a progressive neurological condition.
How did Hollywood respond to Bruce Willis’ retirement?
Some of Hollywood’s biggest stars have sent letters of support to Willis.
Jamie Lee Curtis, Cindy Crawford and Rita Wilson were among those who exchanged messages of support after the Willis family released a statement on Wednesday.
Actress and writer Curtis said, “Mercy and courage! Love to you all!” While supermodel Crawford shared a praying hand emoji.
Cheers star Kirstie Alley tweeted, “Very sad news. I’m so glad Bruce has such a wonderful system of support. Great guy, great actor, great family. A win-win combination.”
Actress Wilson added, “My heart goes out to Bruce and all the family. So grateful for sharing this with us. Keeping you all in our prayers.”
Matthew Marsden, Willis’ co-star in Deadlock, posted on Twitter: “I am so proud to have worked opposite the great Bruce Willis in one of his last films. That’s so sad. Legend.”
Seth Green, whose credits include Austin Powers and Scooby-Doo 2: “I have so much love for Bruce Willis, and I’m grateful for every character he’s given us.
“Hugs and love to the whole family – thanks for sharing it with us all.”
Revealing the news on social media on Wednesday, Willis’ family said this was a “really challenging time” for them and thanked fans for their “continued love, sympathy and support”.
“To the amazing Bruce fans, as a family we wanted to share that our beloved Bruce has some health issues and was recently diagnosed with aphasia, which affects his cognitive abilities,” a statement shared on Instagram read.
“As a result of this and with so much consideration, Bruce is walking away from a career that meant so much to him.”
Willis married actress Demi Moore in 1987 and they have three older children, Rumer, Scout and Tallulah.
The couple separated in 2000 but remained on amicable terms and Willis married actress Emma Heming in 2009.
The couple also shares two daughters, Mabel and Evelyn.
“This is a challenging time for our family and we deeply appreciate your continued love, sympathy and support.
“We are moving through this as a strong family unit, and we wanted to attract his fans because we know how much he means to you, as you do to him.
“As Bruce always says, ‘Live your life,’ and together we plan to do it.”
The post is signed by Emma, Demi, Rumer, Scout, Tallulah, Mabel and Evelyn.
Scout later posted on her Instagram story: “The wonderful outpouring of love I’m experiencing right now absolutely amazes me.
“Thank you all for showing such incredible tenderness and love to my father and my entire family!”
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