Foo Fighters recruited Paul to play drums on one track from their upcoming ninth LP, Concrete and Gold. In a new interview with ET Canada, in which Dave Grohl called the Beatle “the most wonderful guy in the world,” the band detailed how quickly the collaboration came together.

“He hadn’t even heard of the song,” said an unspecified member of the sextet. “He comes in and Dave picked up an acoustic and showed him real quick. He sat on his special drum set that his tech set up for him. I sat there with a drumstick conducting. He did two takes.”

McCartney previously collaborated with Grohl and two other surviving members of Nirvana (bassist Krist Novoselic and current Foo Fighters guitarist Pat Smear) on “Cut Me Some Slack,” an original song recorded for Grohl’s 2013 film, Sound City.

Grohl clarified that Paul isn’t the surprise “pop star” guest Foo Fighters have been teasing for over a month. In June, the singer told BBC Radio 1, “[He or she] sings backup on one of the heaviest songs on the record. And we’re not telling anybody who it is.” But in a recent interview with Rolling Stone, Grohl walked back his phrasing, explaining, “This person is, I think, is more than [a pop star].”

“It was sort of towards the end of the album and this person came up and said, ‘Man, I’d really love to sing on your record,'” the frontman continued. “I looked at [producer] Greg [Kurstin] and said, ‘OK, come in tomorrow and we’ll figure something out.’ So we found a backup part for this person to sing and we decided we were gonna make it our own dirty little secret and see if anyone can figure it out.”