Ariana Grande has revealed that her duet with Justin Bieber was never completed.
The Boyfriend singer posted a photo of them, who share the same manager, in the studio earlier this year, but the Problem chart-topper admitted the track was never finished.
"We were working on it. We were in the studio together. We were going to do it, but then we both got busy," she said. "I had to focus on my stuff and he was focusing on his, and it just sort of didn't really get done."
Ariana, whose upcoming album My Everything features collaborations with the Weekend and One Direction's Harry Styles, hopes the pair's collaboration will eventually happen.
"We feel like we owe it to our fans to do something one day. We will finish it and put it out one day, but it just wasn't the right time," she added.
The 21-year-old singer also admitted she had initial doubts about her No 1 collaboration with Iggy Azalea, Problem.
"Once we wrote it and recorded it, I was like, 'Hmm, I'm kind of scared of this'. It started to intimidate me a little because it felt different for me and it was such a risk with the whispers," she said.
"It took me a lot of time. I had to separate myself from it for a while. For a couple months I didn't even listen to it. I heard it again when it was finally mixed and done and I was like, 'Oh, wow. Hmm, maybe I am completely wrong'. "
Ariana, who appeared in the Nickelodeon series Sam & Cat and Victorious, also revealed she has turned down scripts.
"There were a couple things I really wanted to do, but I had to turn down because of the music," she said. "It disappointed me so much because they were horror-related and horror is my favourite thing in the world."