Liam Neeson has had Bruce Willis on his mind.

The actor is starring in his latest action movie titled "Memory," which opens on April 29. In it, he plays a deadly assassin as he faces Alzheimer’s.

The 69-year-old said he can’t help but think about Willis, who recently retired from acting following his aphasia diagnosis.

"My heart goes out to him," Neeson told the New York Post on Monday. "I think of him every day. It’s particularly poignant, isn’t it? I wish him all the best."

BRUCE WILLIS' NEW MOVIE CO-STAR ON HIS LEGACY FOLLOWING APHASIA, RETIREMENT

Liam Neeson Bruce Willis

Liam Neeson has been thinking about fellow action star Bruce Willis. (Getty Images)

On March 30, it was announced that Willis was stepping away from acting after a diagnosis of aphasia, a condition that causes loss of the ability to understand or express speech.

In a statement posted on Willis’ Instagram page, the 67-year-old actor’s family shared that his cognitive abilities have been impacted.

"As a result of this and with much consideration, Bruce is stepping away from the career that has meant so much to him," read the statement signed by Willis’ wife, Emma Heming Willis, his ex-wife Demi Moore, and his five children, Rumer, Scout, Tallulah, Mabel and Evelyn.

"We are moving through this as a strong family unit, and wanted to bring his fans in because we know how much he means to you, as you do to him," they said. "As Bruce always says, ‘Live it up’ and together we plan to do just that."

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Bruce Willis family

Joining Bruce Willis for his Comedy Central roast are, from left, Rumer Willis, Demi Moore and Tallulah Belle Willis on July 14, 2018, in Los Angeles, California. (Phil Faraone/VMN18/Getty Images For Comedy Central)

In "Memory," a remake of the 2003 Belgian film "The Memory of a Killer," Neeson's character must face his greatest battle, a harsh reality some face as they get older.

The action star admitted to the outlet that he has a fear of Alzheimer's, a progressive disease that impacts memory and other vital mental functions.

"It has crossed my mind a few times, especially when you can’t remember a name of an actor I worked with two or three years ago," said Neeson. "That bugs me. But maybe we all suffer that."

"In doing some research for this, I watched some very traumatic documentaries on the affliction of Alzheimer’s and dementia, and read some books on it of course," he shared. "And I have a friend in Ireland, who is older than me, [who] has very definite early stages of dementia, which is traumatic to see... It is a horrible affliction. It really is."

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Liam Neeson Natasha Richardson

Liam Neeson's wife, Natasha Richardson, passed away in 2009 at age 45. (Shawn Ehlers/WireImage)

"I know several actors in London... who have lost the ability to learn lines," Neeson continued."They just can’t learn the material. And these are actors who have given extraordinary performances on stage and on film and television."

Neeson has faced his own personal heartbreak. His wife, actress Natasha Richardson, passed away in 2009 at age 45 from a brain injury following a skiing accident. The widower told the outlet that he doesn't see himself getting married again.

"No, I think I’m gonna be on my own," he said.

Willis' diagnosis has sparked conversations about aphasia, which has many potential causes. It often occurs after a stroke or head injury, but can also develop gradually due to a slow-growing brain tumor or a disease that causes degenerative damage, like Alzheimer’s disease. It’s treated primarily with speech therapy and learning non-verbal means of communication.

BRUCE WILLIS AND THE CRUELTY OF APHASIA

Bruce Willis

Bruce Willis and his wife, model Emma Heming Willis. (VCG/VCG via Getty Images)

Willis’ family didn’t divulge what caused his aphasia. Representatives for the actor declined to comment.

The news about Willis, one of Hollywood’s most beloved actors, immediately spread online as fans reacted. His four-decade career has amassed more than $5 billion in box office worldwide,

Willis had been working steadily and frequently. Renowned for films like "Die Hard," "Pulp Fiction" and "The Sixth Sense," Willis has in recent years churned out straight-to-video thrillers. Last year, he starred in a staggering eight films. Most came and went quietly, including titles like "Cosmic Sin," "Out of Death" and "Deadlock."

Most recently, Willis starred in February’s "Gasoline Alley" and "A Day to Die," released in early March. Willis has already shot at least six more films due out in 2022 and 2023, including "Die Like Lovers," "Corrective Measures" and "The Wrong Place."

The Associated Press contributed to this report.