Paul McCartney has admitted that he didn’t recognise his own guitar when he first heard his ‘FourFiveSeconds’ collaboration with Kanye West and Rihanna.

• Read more: Paul McCartney – ‘McCartney III’ review: an unpredictable quest of musical evolution

The 2015 track, which has been covered by everyone from Drake to James Bay, peaked at Number Four on the US Billboard chart, and it helped McCartney set a record by ending the longest break between Top 10 singles on the chart.

Speaking on The Tonight Show Starring Jimmy Fallon on Thursday (December 17), McCartney said that he didn’t even know he was making a song at first.

“It was only two months later when I got a track sent to me,” McCartney said. “I didn’t think I’d done anything, but suddenly I got sent ‘FourFiveSeconds’ with Rihanna.”

He added: “I like that one. And I had to say, ‘Am I on this record?’ He said, ‘That’s you doing that guitar.’ So they’d sped it up so it wasn’t recognisable.”

Elsewhere during his appearance on Fallon, McCartney talked about being a self-taught musician.

“I wasn’t trained in anything. Nothing. I really wasn’t,” he said. “They tried to train us in stuff, but no, I didn’t get trained in anything. But there’s still time, I might learn. I might take lessons. Who would I take lessons from?”

McCartney released his new solo album ‘McCartney III’ earlier this month, the third in his trilogy of self-titled albums dating back to 1970.

Reviewing ‘McCartney III’, NME wrote: “If future archaeologists take this three-album series as a significant marker of his solo half-century, they’ll conclude that Paul McCartney never stopped liberating.”

Meanwhile, McCartney recently opened up about his friendship with John Lennon in a new interview.