Sir Paul McCartney relished the "freedom" that came with making an album at home

He explained: "If you're on your own, you can have an idea and then very quickly play it. Whereas, with a band, you've got to explain it.

"Sometimes that's great ... but when you're just noodling around on your own, there's just a sense of freedom."

The upcoming album follows 1970's 'McCartney I' and 1980's 'McCartney II' - but the chart-topping icon never set out with the ambition of making his latest record.

Speaking to BBC 6 Music, he shared: "Most of it's new stuff. There are one or two [songs] that I hadn't finished and, because I was able to get in the studio, I thought 'OK, wait a minute, what about that one?' So I'd get it out and think, 'Ugh, oh dear.' And you'd try to figure out what was wrong with it, or why you didn't like it.

"In some cases the vocal or the words just didn't cut it, so you'd strip it all down and go 'OK, let's just make it completely different'.

"When I'd done them, I was going 'Well, what am I going to do with this?' And it suddenly hit me: this is 'McCartney III'. You've done it all yourself, like the others, so this qualifies."

McCartney explained that he was simply trying "to have fun" during the recording process.

He said: "Because I wasn't aiming at a proper record release, I was just having a go. So I think it has ended up being exactly what it is - which is me not really trying very hard, except to have fun."