What's the most British thing about you?
I'm attracted to things that aren't simply pretty – there has to be an element of darkness to it, like the beauty of the smog. That comes from growing up in London. I also find it very hard to say something intimate without following it with a joke. "Quickly, make it sarcastic! Pull it back!" I don't know if that's a British thing or just a Welch family thing.
What was your favourite book as a child?
Little House on the Prairie. For Christmas, my aunt gave me and my sister little custom smock prairie dresses, and we would make a prairie in our house, with a lake made out of towels. I may have sensed something unsettled in my parents' marriage; they eventually divorced. The book might have symbolised some kind of domesticity or stability to me.
What's the most recent book you've read?
I've been reading Patti Smith's M Train. She's given us some really beautiful parts of herself with her [two memoirs]. It's incredibly inspiring the way she can truly be herself in the public eye.
What are your earliest musical memories?
My dad has great taste; he used to play me the Velvet Underground, the Smiths and the Stones. He was excited when I got to sing "Gimme Shelter" with Mick Jagger. He said, "You know, I always thought that was the song you were supposed to sing."
It's hard to imagine, but you were really into skate punk.
The first CD I ever bought was Green Day's Dookie. It was my first clue that there could be a whole identity around the music you liked. I had the shoes and the world's baggiest cords. The only thing I didn't have was a skateboard.
You even recorded a complete cover of Green Day's Nimrod a few years ago.
I was going to see punk bands, and [producer-artist] Dev Hynes and I bonded. We were talking about how we loved Nimrod, and we recorded it in his kitchen with just his guitar. It's out there on the Internet! Later, I met Billie Joe Armstrong, and he told me he liked it. My 13-year-old self's head was exploding somewhere in the past.
What is the best part of success?
I love to experiment, to create a world to get lost in. I can do that as a job, down to the outfits and the staging.
Do you ever go too far into that world?
I can go off into flights of fancy, and they're not always positive. I can panic quite easily. Sometimes, I have to breathe and be like, "Actually, what's happening right now? Is that real? You're in your house, nothing is actually happening. Oh, OK."
What's the best advice you've ever received?
When I got off tour a few years ago, I tried to keep living as I had been. You want to keep the party going, but you're just in your own house. I was like, "Oh, my life is in chaos, and my relationships are so messed up. What am I doing?" A friend said, "Why don't you try not drinking for a while – see what happens?" [Laughs] I was willing to try anything at that point. It definitely helped me write my last record.
How do you relax when you're not on tour?
When you're on the road, you're like, "Oh, my God, touring is so stressful." Then you come back and struggle to fit in all these things that you miss from normal life – seeing friends, seeing my mum. You've got to do your own laundry, too, and I can even stress myself out about getting enough rest. By the time I have to leave again, I kind of want to get back on tour, because I can finally relax.
You and Adele sang in the same club early in your careers. What do you remember from that night?
I think it was in the Lock Tavern in Camden – tiny room, lots of people crowding around. I did my yelling kind of singing, and then she came on and sang and just played her guitar. I couldn't really see her, but this voice just lifted up over the people, and I was like, "That is an extremely special voice." I went home and wrote a song immediately, though it wasn't up to the level of "Rolling in the Deep".
What's an important rule to live by?
If something feels different, or uncomfortable, it means you're growing. My last album was quite exposing. Not having effects on my vocals was terrifying. I would ask my producer, "Please, can you just put some reverb on?" I was nearly crying. He was like, "No, you have to just let your voice be the way it is. You have to be vulnerable."
What advice would you give your younger self?
There are certain sartorial choices I would not make, in hindsight. I had black lipstick. I was wearing capes stapled to me. I got famous when I was about 21. It was totally thrilling and also completely terrifying. You're scared and want something to shield you, so you think you've got to have more hair, more makeup. To live in this creation, in this kind of magical alternate universe, kept me safe. But I wouldn't take any of that back. I would just say to that person, "It's going to be OK."