Billie Eilish was accused of not being "authentic" or "honest" during a studio session for her latest album.

The pop star's brother Finneas - who has produced all of his sisters records - has revealed the pair got into an argument while they were working on her third album 'Hit Me Hard and Soft' because he was convinced Billie could do better,

During an appearance on YouTube show 'Hot Ones Versus', Finneas explained: "I think the longest, biggest argument was during a period of transition in maybe both of our lives where we were just trying to be kind of honest.

"To give [Billie] credit, I was very much high and mighty about, like, ‘You’re not being honest or authentic enough.' So I learned a lot from being too egocentric in that process."

Billie added she was also annoyed about her brother putting his bare feet on the sound desk, adding: "He’s a lot of times barefoot, a lot of the times in very filthy shoes ... My face is right there [near the desk where his feet are]. And actually we filmed so much in making the album that almost all the footage is his feet and then me."

The siblings previously opened up about the difficult times during the making of the album in an interview with Apple Music 1‘s Zane Lowe in May, with Finneas claiming Billie wasn't being vulnerable enough.

He said: "I was like, ‘Subject-wise, I’m not being led into what you’re actually feeling, and I think that there are real guards up'."

Finneas confessed he even reached a point when he considered walking away from music, and Billie revealed she understood exactly how he was feeling.

She said: "It was very interesting because I saw myself in that. I was like, ‘I have felt that way and you have always been the thing that keeps the ship moving, and now you feel that way. What does that mean for us? And what are we going to do?"