Billie Eilish thinks ''all the rappers'' are ''lying'' about themselves.

The 18-year-old singer has hit out at the number of stars who present a false image of their wealth and lavish lifestyles and insisted it's easy to ''see through'' people who claim to be rich but really aren't.

She said: '''Bad Guy' is more about people that are always lying about themselves. A lot of it is about a lot of artists right now, a lot of rappers.

''I feel like pretty much all the rappers right now are lying, about how much money they have and about their house and their clothes etc.

''It's like, 'Shut up, you don't have this.' It's just annoying.

''And it's so easy to see through people when they talk about their money. They have nothing else, so that's all they talk about.''

Billie co-writes her songs with her brother, producer Finneas O'Connell, and they have always had a good working relationship, even when they have their disagreements.

And Billie revealed they haven't changed anything about the way they collaborate since their early days of creating together.

She told heat magazine: ''There's a lot of disagreeing and agreeing - everything you can possibly disagree about and everything you can possibly agree about with him. But it makes everything closer to home. Does that make sense?

''Like when we're on tour, I go with my brother and my mum comes and my dad comes. We're leaving our home but we're all still home a little bit.

''But writing with him, it was so natural at first. It really wasn't disingenuous, it was just like, 'We live two feet away from each other, why don't we do this together?'

''We still make stuff in the same room, we don't need a big studio or whatever. We use my brother's tiny little room in our tiny little house and it still works for us.''