Van Morrison will “never sing a lyric the same way twice”.
The 79-year-old star considers himself to be a jazz singer because he’s “always improvising” and switching things up when he performs.
In an interview with The Sun newspaper, he explained: “I don’t see myself as being part of the rock and pop world.
“I am basically a jazz singer. No matter what genre I’m working in, I’m always improvising.
“Jazz is always forward moving and forward looking.
“I learned from the Louis Armstrong school. Louis said, ‘I never sing a song the same way twice.’
“That kind of stuck. And I never sing a lyric the same way twice either.”
Van likes to sing songs that are as “relevant” today as they were when they were written.
He noted: “When I do songs live, I often change lyrics here and there, bringing them up to the present.”
Van admits he no longer relates to his 1967 classic ‘Brown Eyed Girl’ and cringes when he sings it live.
He confessed: “How can a 79-year-old guy sing about something he wrote when he was 20?
“It’s basically a teenage song. I can’t relate to it much now, you know.”
Elsewhere, Van revealed he always wanted to record a duet with Willie Nelson, and was thrilled to do two songs, ‘What’s Wrong With This Picture?’ and ‘Steal My Heart Away’, with him on his latest LP ‘New Arrangements And Duets’.
He said: “It had been on my mind to do a duet with Willie Nelson for a long, long time but I didn’t get the opportunity.”
After sharing the same stage, the pair headed to a studio in Pittsburgh to get to work and hit it off instantly.
Praising the 91-year-old folk legend, Van said: “It was absolutely fantastic. Very relaxing and very professional. Willie came in and delivered.
“I played those songs for him and he was into them. There’s not a lot of pondering with this stuff. The less back and forth the better.
“Willie covers all the bases and, to me, he’s very similar to Ray Charles. I like his work and I heard he liked mine.”
‘New Arrangements and Duets’, which is out now, also features Joss Stone, Curtis Stigers and Kurt Elling.