Sir Paul McCartney's final album of the '80s, Flowers in the Dirt, is regarded as one of his best of the decade.

He teamed up with new musicians, new producers and a new songwriting partner in the form of Elvis Costello and it inspired his first world tour in 10 years.

Now, as the record is re-released, complete with previously unheard demos, Sir Paul speaks to BBC 6 Music's Matt Everitt about collaborating with Costello, Kanye West and Michael Jackson - but why he'll never work with anyone better than John Lennon.

Sir Paul also reveals he's working on a new album with Adele's producer, and what he thinks his musical legacy will be.

Do you learn something from every person that you collaborate with?

My thing with collaboration, I know I can never have a better collaborator than John. That is just a fact. So I don't try and escape it. I just know there's no way I can find someone now who's going to write better stuff with me than I wrote with John. But having said that, I'm interested in working with other people because they bring their own particular thing to it.

If you're thinking of someone like Stevie (Wonder), he works by just making something up on his keyboards. You invite him to dinner, he shows up 10 hours later because he was fiddling around on his keyboard. He's such a musical monster and such a genius, that's what you learn from him.

Michael Jackson, we just sat upstairs in this office and I tinkled on the piano and we just made up a song there. Now with Kanye, I had no idea what was going to happen because I knew it wasn't going to be two acoustic guitars opposite each other. So I thought, 'Well, here goes nothing'.

The one provision I said to everyone, I said, 'Look, if I feel this doesn't work out, then we just won't tell anyone. Kanye who? I didn't work with him!'

Image copyright Getty Images Image caption Kanye West, Rihanna and Sir Paul collaborated on 2015's FourFiveSeconds

I just was myself and I told Kanye various stories that had inspired me musically. One of them was how the song Let It Be arrived, which was through a dream I'd had in which I'd seen my mother, who had died 10 years previously.

But I was so inspired by that that I wrote the song. I told Kanye that, because he'd lost his mother. So then he wrote a song called Only One when I was just noodling around on the electronic piano. So he got the melody, I put the chords in and the style and that's how it happened.

Did you go into Flowers In The Dirt feeling like it was kind of a bit of a reset?

I think so. I'm just bringing up my family, and then a point will arrive where I just think, 'OK, I've got some songs. I should get busy, I should record these. We should go out on tour. It's time'.

And that's what happened round about that time. It was suggested to me that I work with Elvis Costello as a partnership and it seemed like a good idea. I thought, 'Well, he's from Liverpool, he's good' - which helps - and we have a lot of things in common and so I thought, 'Well that could work'.

Image caption Sir Paul said he worked with Elvis Costello in a similar way to how he had worked with John Lennon

Was it writing nose-to-nose? Two acoustics, strumming at each other?

There's a million ways to write, but the way I always used to write was with John and it would be across from each other, either in a hotel bedroom on the twin beds, with an acoustic guitar and we're just looking at each other. He'd make up something, I'd make up something and we'd just spin off each other. The nice thing for me is seeing John there, him being right-handed, me being left-handed, it felt to me like I was looking in a mirror.

Obviously, it was very successful. So that was a way I had learned to write and it was the way I liked to write and Elvis was very happy to work like that. So it was like a repeat of that process, and so he was John, basically, and I was Paul.

I have to ask you about Chuck Berry. Obviously a massive musical hero of yours. What was he like? Did you work with him much?

I didn't work with Chuck. I met him. He came to one of our concerts when we were playing in St. Louis, his home town, and he came round backstage. It was great to meet him and just be able to tell him what a fan I was.

When I think back to being in Liverpool pre-Beatles, when we were all just kids learning the guitar with the dreams of the future, we suddenly heard this little thing, Sweet Little Sixteen. We never heard anything like that, and then when Johnny B. Goode came along, all of his fantastic songs, Maybellene. All these songs about cars, teenagers, rock 'n roll music, was just so thrilling.

Image caption Paul McCartney with BBC 6 Music's Matt Everitt

Looking at the wave of tributes that followed Chuck Berry's death, do you ever wonder how are you going to be remembered?

I think you do and you put it out your mind. I don't get into it, really. I remember John once, saying to me, 'I wonder how I'll be remembered. Will they remember me well?'. And I had to reassure him. I said, 'Look at me. You are going to be so remembered, you've done so much great stuff'. But it was funny - you wouldn't think John would even have a remote bit of insecurity about it. But I think people do. Luckily, it won't matter because I won't be here.

On a more positive note, what's next?

I'm making a new album which is great fun. I'm working with a producer I first worked with two years ago on a piece of music I'm doing for an animated film. Since then, he went on to work with Beck and got album of the year with Beck. Then he went on to work with Adele and has just got song of the year, record of the year, with Adele, and just got producer of the year.

So my only worry is, people are going to go, 'Oh, there's Paul going with the flavour of the month'. But he's a great guy called Greg Kurstin and he's great to work with. So yeah, I'm at it. Beavering away, doing what I love to do. As Ringo says, 'It's what we do'.

To hear the whole of Matt Everitt's interview with Paul, listen back to the BBC 6 Music Breakfast Show, broadcast on Thursday morning.

The reissue of Flowers in the Dirt is out on Friday, 24 March.

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