I found this but Idk if the sources are actually genuine. A lot of things that I've read about Gaga in the past say that "A source close to her has confirmed (whatever the particular rumour was at the time)" and it always turns out to be false. For example, when the Bradley Cooper baby rumours first started last year, all the reports said "A source close to Gaga has confirmed she is glowing and hiding a baby bump" and that obviously turned out to be false. Plus what I said earlier about Ariana confirming her own new music makes it seem less likely to me that they're collabing and they're just coincidentally working in the same studio
@JJ_Monster1999 I think I heard her say it in a video where she was playing a game with Elle Magazine and she was given a word and 10 secs to sing that word in a song & she did one and told them it was her new song