Sir Paul McCartney has said he's glad he didn't listen to critics of his music after The Beatles, because he "might have given up".

Sir Paul is re-mastering his albums Tug of War and Pipes of Peace, and spoke about being "proud of his music in retrospect" with BBC Radio 2's Dermot O'Leary.

"I do yeah, in fact one of the things was Wings were getting a bad rap at that time because it was post Beatles, and anything you did or I did that was solo was stood up against The Beatles," he said.

"So you tend to go along with that, and I went along with a bit of that thinking 'well it's never gonna be that good but I'll do it because I love doing it'."

"And then you listen to it back and think 'this is better than I thought it was'. So that's great to do, to really listen back and think 'I'm glad I did that, glad I kept going', because you know if I listened to the critics I might have given up."

He also spoke frankly about the day Beatles star John Lennon was killed.

Lennon was shot in New York in December 1980 by Mark David Chapman.

Sir Paul recalled that he had a studio session booked in London that day, and that when his manager phoned him with the news he was "floored".

He spent the day with producer and friend George Martin in the studio, so he could "be with people who could help you grieve and that's what I decided to do so it was a very strange day in the studio".

He added: "You just try to work through it and obviously every second of the day was drenched in the fact because you just kept stopping and going 'oh my God'.

"You know it was so shocking and you couldn't put it into words. None of us could say anything at that time, it took a while before you could say 'ah remember that, remember John, wasn't that great'.

"I could put my anger into words for the guy who killed him. That's about all I could do that day."

He also spoke about spending time with the late Michael Jackson and working on the song Say Say Say.

"He came over to England and he hung out with me and the family," Sir Paul said, "We had him to dinner, he didn't eat much."

"I said 'Michael come on eat ya supper', but it was always a laugh. It was always a laugh. It was really nice actually because the guy that was with him who was not his minder, not his bodyguard, not his manager - he was just sort of like his companion, an older black guy - Billy - he took me aside and said 'you know this is really good for Michael'. I think it was the family life and Michael could just hang."

Sir Paul's re-mastered albums are due for release on 2 October.