The Swedish pop star recently revealed she has scrapped collaborations with the 'Thank U, Next' singer and Ed Sheeran from her upcoming album.
However, she’s tempted to put out the track with Ariana, though fans will have a hard time trying to pinpoint her voice.
Zara told the Daily Star newspaper's Wired column: "We did these full-on choir back-up vocals in the staircase.
"I might release that song, but you won't be able to hear that it is her in all of these vocals in that song."
The 22-year-old singer had previously recorded new tracks with both Ariana and Ed but decided that she doesn't want any collaborations on the new record - the follow-up to her 2017 debut, 'So Good', which is called 'Poster Girl'.
She explained: "I don't know if I'll put it on the album, it's not on there right now.
"Also, sorry to say to Ariana fans, you can't really hear her on there anyway because we did a gang vocal thing, so there's like ten people singing at the same time. But she's so sweet.
"It's a really good song. It's about not feeling your best, being anxious and wishing you were someone else sometimes.
"There are definitely songs [with Ed], there's so many the universe will probably never be able to hear.
"We worked together for the album but I've been working on this album for three years."
However, Zara teased that fans could hear the tracks in the future.
She said: "I still really like the artists so I'll save them and maybe they'll come out in the future."
Meanwhile, the ‘Ain’t My Fault’ hitmaker is contemplating returning to school as she never actually graduated.
She told the tabloid: “I only commit to things that I think are fun and I can't finish stuff that I don't think is fun or interesting. I think it's impossible.
"That's why I still haven't graduated school.
"I shouldn't have said that ... but I am smart, I swear I am."