How Kacey Musgraves' Late Mentor John Prine Inspired Her Witchy New Song 'Cardinal'

Kacey Musgraves dropped her latest album on Friday, and it includes a sweet nod to her late friend John Prine.

In the zine available for purchase with her new record Deeper Well, out now, Musgraves reveals that album opener "Cardinal" was inspired by the country icon, who died in April 2020 of complications from Covid-19, writing: "When cardinals appear, angels are near."

"Unexplainable things started happening and cardinals started showing up on my doorstep soon after my good friend and mentor passed, John Prine," Musgraves, 35, writes in the zine. "He always had a big connection to cardinals and felt that they were messengers from the spirit realm. He inspired this song, no doubt."

"I saw a sign / Or an omen / On the branches / In the mornin' / It was right after I lost a friend / Without warning / Words unsaid / Scarlet red / Cardinal / Are you bringin' me a message from the other side / Cardinal / Are you tellin' me I'm on somebody's mind / Don't leave me behind," Musgraves sings on the track.

The lyrics complement the track's otherworldly production, as well as the overall aesthetic of the album, which Musgraves succinctly described as "soft nature cottage witch" to The Cut.

Musgraves was a longtime fan of Prine before they became friends and collaborators once she found Nashville fame. She joined Prine in 2015 aboard his Cayamo: A Journey Through Song cruise, on which they sang his hits “Illegal Smile” and “Paradise”; and in 2017, they reunited to sing his classic “Angel from Montgomery” at the Red Rocks Amphitheatre.

“John Prine singlehandedly impacted my songwriting more than anyone else. He’s the king of turning phrase but keeping it simple,” Musgraves told PEOPLE in an exclusive statement following his death four years ago. “They say you shouldn’t meet your heroes, but you’ll never meet someone as truly genuine as he was.”

At the time, Musgraves added: “There are two times I’ve ever seen my dad cry: my Memaw’s funeral and the time I got to play with John Prine."

"Cardinal" isn't the first song of Musgraves' that Prine has inspired: He was also the muse behind her early track "Burn One with John Prine."

As for the rest of Deeper Well, Musgraves recently told PEOPLE the record is reflective of the peaceful time she's enjoying in her life.

"It's definitely my most grounded time period yet. I'm 35 now, and I know myself better than in previous years, previous albums, and I just feel like I'm right where I need to be," she said. "Ultimately, the song sums up where I'm at in my mid-30s and really evaluating what love means to me, what friendships mean to me, what are the things that I need, what is really important to me, what's serving me, what's not serving me, and taking stock of that and making room for the things that actually do really matter. This life is so short. I think that you have to be a little bit ruthless in removing obstacles for growth."