Because Gaga doesnt want to? But Sia has said in an interview that she would love to write with Gaga. And I'd be here for that

She didn't go back to RedOne RedOne asked Gaga to be on his debut album and then they probably started talking about new music again etc. and started working on LG5 too.
Gaga would never go back to Red, just for success, even if she wants it, she won't do it, she is stubborn as ****.


Sia is a big songwriter, Gaga can work with her, but the situation will be more like Gaga x Diane Warren, rather than Gaga x Red One (who is the main producer, Gaga the main writer). Furthermore Sia usually is the sole writer, she comes up with the direction etc. whereas Gaga has her OWN direction for her new album and if Sia somehow fits that, Gaga would work with her (tho Gaga prefers to write with a producer, thus they can take a lot of each other).

I am sure that Gaga would like to work with Sia, but only if she feels like it. And same for Sia. The difference is that Gaga comes up with the direction of her songs, albums etc. and then writes lyrics melodies - the same thing that Sia does.

Whereas a producer can add a lot more (and different) things to something that a writer like Gaga/Sia would create. Hence why I have always thought that Katy writing with Bonnie etc. is a bit pointless.

I was actually very surprised Sia x Adele happened, but I was also surprised Gaga x Diane Warren happened so yeah..

Gaga writes/composes and co-produces her own songs so there really is no need.

I don't think Gaga would nail a Sia song, and Gaga knows it herself it's not her style.