For Hearts That Strain, Jake Bugg added a Nashville vibe to the tracks, joining forces with a host of other musicians that live in the Tennessee capital. However, the guest vocalist on this song is Los Angeles resident Noah Cyrus, younger sister of Miley. It was after Bugg's producer David Ferguson played the track to her father, Billy Ray Cyrus, that the 17-year-old got involved.

"When I was back in London, Billy dropped into the studio I had been working in Nashville and heard the song (Waiting) and really liked it," Bugg told the London Evening Standard newspaper.

"He thought Noah would be perfect for it, and she recorded her parts while she was in LA," he added. "I've never met her, which is a bit weird but that's the way it goes nowadays."

Bugg praised Noah for improving the track. "She made it sound much better," he admitted. "When my voice comes in it sounds terrible, but when she's singing it sounds all right."