A lot has changed for the British singer since her last album, released when she was 21, including becoming a mother. She explains in her letter that those changes are reflected in the theme of her new album.

She writes, "My last record was a break-up record and if I had to label this one, I would call it a make-up record. I'm making up with myself. Making up for lost time. Making up for everything I ever did and never did. But I haven't got time to hold on to the crumbs of my past like I used to. What's done is done."

That last album earned her six Grammy awards and she continues the tradition of naming her albums after her age when they were released, beginning with her debut "19". She has not yet revealed a release date for the new effort.

Here is her full letter: "When I was 7, I wanted to be 8. When I was 8, I wanted to be 12. When I turned 12, I just wanted to be 18. Then after that I stopped wanting to be older. Now I'm ticking 16-24 boxes just to see if I can blag it! I feel like I've spent my whole life so far wishing it all away. Always wishing I was older, wishing I was somewhere else, wishing I could remember and I wishing I could forget too. Wishing I hadn't ruined so many good things because I was scared or bored. Wishing I wasn't so matter of fact all the time. Wishing I'd gotten to know my great grandmother more, and wishing I didn't know myself so well, because it means I always know what's going to happen in the end. Wishing I hadn't cut my hair off, wishing I was 5'7". Wishing I'd waited and wishing I'd hurried up as well.

"My last record was a break-up record and if I had to label this one, I would call it a make-up record. I'm making up with myself. Making up for lost time. Making up for everything I ever did and never did. But I haven't got time to hold on to the crumbs of my past like I used to. What's done is done. Turning 25 was a turning point for me, slap bang in the middle of my 20s. Teetering on the edge of being an old adolescent and a fully-fledged adult, I made the decision to go into becoming who I'm going to be forever without a removal van full of my old junk. I miss everything about my past, the good and the bad, but only because it won't come back. When I was in it, I wanted out! So typical. I'm on about being a teenager, sitting around and chatting sh- and not caring about the future because it didn't matter like it does now. The ability to be flippant about everything and there be no consequences Even following and breaking rules� is better than making the rules.