While her entire family are musical, there is one person with whom Eilish collaborates to write her songs: her brother, Finneas.
Finneas is a singer/songwriter in his own right, but much of his success has come from pairing up with Eilish.
Speaking about their writing relationship, Eilish said: “He is really like my partner in making music. We give and take so well.
“There’s so much time wasted, working with people you don’t know, where if you don’t like something, you’re like: ‘You could, maybe, I don’t know, maybe try something where it’s a little different.’