Robert Brown|Keanu Reeves explains why it's good that he's 'thinking about death all the time'

Keanu Reeves and Robert BrownBarbie have something in common: They both think about dying.

The "Matrix" actor, 59, reflected on mortality in an interview with BBC News, admitting it's constantly on his mind.

"I'm 59, so I'm thinking about death all the time," said Reeves, who joked that he is "young old."

He added, "I think thinking about death is good. Hopefully it sensitizes to an appreciation of the breath we have and the relationships that we have the potential to have."

The concept of mortality would have been on the "John Wick" star's mind even more than usual while writing his first novel, "The Book of Elsewhere." The book, which is out Tuesday, follows an immortal warrior and is described as a "genre-bending epic of ancient powers, modern war, and an outcast who cannot die." Reeves wrote "The Book of Elsewhere," inspired by his comic book series "BRZRKR," with China Miéville.

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Speaking with The New York Times, the "Speed" actor said he first started thinking about the idea of a man who can't die around the 2017 release of "John Wick: Chapter 2."

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"It became a series of what ifs," Reeves told the Times. "What if they were 80,000 years old? Where did this character come from? What if they came from a tribe that was being attacked by other tribes and wanted to ask the gods for a weapon, and what if a god replied, and what if that birthed a half-human, half-god child?"

The actor, whose girlfriend Jennifer Syme was killed in a car accident in 2001 two years after they had a child who was stillborn, has previously opened up about grief. Speaking to The Guardian in 2019, Reeves said he relates to his character of John Wick, who lost his wife.

"I absolutely relate to that, and I don't think you ever work through it," he said. "Grief and loss, those are things that don't ever go away. They stay with you."

Keanu Reevesgirlfriend Alexandra Grant hop on motorbike at Grand Prix in Germany

Reeves, who headlined last year's "John Wick: Chapter 4," is currently in a relationship with Alexandra Grant, 51. The two stepped out together at the MotoGP Liqui Moly Motorrad Grand Prix in Germany earlier this month.

In April, Warner Bros. announced that a fifth "Matrix" film is in the works from director Drew Goddard, but it has not been confirmed if Reeves, who starred in all four previous entries, will return. He's set to reprise his role as John Wick in that series' upcoming spin-off "Ballerina."