When U2 recently announced their upcoming album Carnaval De Luz, one note stood out: The LP features the final vocal recording by Dolly Parton.

She contributed to the album-closing song on Carnaval De Luz called “Torn.” In a conversation with Rolling Stone, Bono revealed that he initially approached Parton to collaborate on an Irish folk music side project.

“She said, ‘That’s a little too Irish for me,'” Bono explained, recalling Parton’s initial reaction to the material. “But she said, ‘I got this song. It’s called ‘Torn,’ and do you want to see where you can take it somewhere else, maybe?’”

Bono and Snow Patrol’s Johnny McDaid put their spin on “Torn,” writing lyrics about a mother watching her family fall apart. Parton liked it and agreed to contribute vocals. “She sang her heart out,” Bono noted, “and I cannot believe that’s an 80-year-old woman.”

‘She Got Out of Bed to Sing This Song’

Parton was already in declining health when she recorded her parts for “Torn.” “When she got ill, she got out of her bed to sing this song,” Bono said. “And you can hear that. And I can’t even listen to it now.”

The news release announcing Carnaval De Luz described “Torn” as “a tender country song detailing broken family ties that holds wider resonances.” The final mix of the tune received Parton’s approval before her death.

READ MORE: 31 Dolly Parton Rock 'n' Roll Covers

“Dolly loved it,” Carnaval De Luz producer Jacknife Lee confirmed. “She was so proud of her vocal and the recording. She was thrilled with it. We were very nervous that she might not approve or would be uncomfortable with it, but she loved it.”

For Bono, the pain of Parton’s death remains fresh. However, he’s grateful for the time they had together. “It’s very moving to have had these intimacies with such a figure,” Bono said. “The fact that they’re not there now, in any way you can call back, other than through her songs, is very sobering.”