Pals Keith Urban and Richard Marx unveiled their latest collaboration on Friday — but it’s not exactly new to them.

According to Marx, "One Day Longer" is a song they wrote years ago that ended up taking space in his laptop. One day, the singer-songwriter decided to give it another listen. Now, it's the first of five country songs from his upcoming album "Songwriter," which is set to be released Sept. 30.

"I sent Keith a voice note saying that I was putting out ‘One Day Longer’ and he texts me back and he says, ‘I have no recollection of that song, but it sounds really good," the 58-year-old told People magazine. "He sounded like he couldn’t believe that we would write something so good together."

Marx and Urban have known each other for decades. They have been writing partners on several of Urban’s hit songs, including "Everybody," "Better Life" and "Long Hot Summer."

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Grammy winners Richard Marx (left) and Keith Urban are longtime pals and writing collaborators. (Rick Diamond/Getty Images for BMI)

"When we write a song, Keith is always over the moon about it on Monday and by Wednesday he’s not into it anymore," Marx told the outlet. "It goes from ‘This is the greatest song that’s ever been written by any two people ever’ to ‘I have no interest in this song whatsoever.’ So I’m used to the sort of bipolar thing that happens when I write with him."

According to Marx, Urban was initially into "One Day Longer" — but then something got in the way.

"I remember Keith saying to me… ‘I love this song but I’m really hungry right now and I hate everything when I’m hungry,’" said Marx. "A couple of days later, he was no longer into it."

But there’s one person who’s already a fan of the song — Marx's wife, Daisy Fuentes. The pair said "I do" in 2015.

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Richard Marx Daisy Fuentes

Richard Marx said his wife Daisy Fuentes was impressed with his latest song. (David Livingston/Getty Images)

"Daisy loves this one," said Marx. "And I would say that that’s not a given with her. She’s honest when it comes to the music that I do."

In June, Urban returned to touring after nearly four years. Previously in January, the 54-year-old took over some spots that were left open by Adele’s cancellation at Caesars Palace in Las Vegas.

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Keith Urban has been keeping busy touring this year. (Roy Rochlin/Getty Images)

Urban's own Las Vegas residency was interrupted by the COVID-19 pandemic. The country music star was only able to perform four shows before the pandemic shut down the live music industry in 2020. The "Blue Ain't Your Color" singer resumed the residency in September 2021.

The Associated Press contributed to this report.