The 'Anything Could Happen' singer, who is dating dubstep musician Skrillex, confessed that her busy career often makes her feel alone.
She told Culture: "If someone asked me what emotion I felt the most it would be loneliness. My boyfriend travels around the world constantly.
"We see each other maybe once a month. So there's that, but there's also the loneliness of feeling you're the only person who can do things the way you want to do them.
"I can be in a room with a bunch of friends and still feel pretty alone. I think I've always been like that, though."
The singer will release new album Halcyon as her second studio record in the UK on October 8 and a day later in the US.