Paul McCartney says that, following the death of his former Beatles bandmate John Lennon, there were times he feared for his life.

Speaking with Uncut, he adds he was on "high alert" after Lennon's shooting and recalls one time when he spotted several armed men outside his apartment.

"It was weird because in the days that followed it, I was sitting in the house," he began.

"We had a little perimeter fence, mainly to keep foxes out, because we had some chickens.

I'm aware of security threats, so I'm on high alert and I look out and I see someone with a f*****g gun, like a machine gun, an assault rifle - 'Wha?!'

He's in full military gear, and then I see there's a whole patrol of them. I'm going, 'Holy s**t, what's going on?'."

The North American leg of Macca's Out There tour begins at Nationwide Arena in Columbus on October 13.