Morrissey doesn't sing some of his older songs live because they are "mating calls".
The 'Boy With the Thorn in his Side' singer recorded four albums with The Smiths between 1982 and 1987 before embarking on a successful solo career, but feels some of his older tracks are inappropriate to sing live now he is 51.
He told BBC Radio 4: "When you write or record a song when you're in your 20s and they you're singing it when you're in your 50s you have to look at yourself and decide if you look silly, or sound silly now singing those words. But I think for the most part I don't.
"Many of the earlier songs were like mating calls, unanswered of course, and I have to think very seriously about trying to sing them now because, obviously, of the dreaded subject of age.
He declined to say which songs he was referring to however, adding: "I have to consider how people viewing me will see me as I sing those words. It's a minor consideration but it's a consideration nonetheless."
Morrissey - who has released nine solo albums - never felt his career would last as long as it has and is "very surprised" he is still making records.
He added: "It hasn't been the easiest journey, initially I thought if I could do one maybe two albums that would be extraordinary.
"But I only ever wanted to sing. To me that was the ultimate power and the ultimate form of expression, and that's what I wanted to do."