[norain]

I'm pretty sure they worked together because they were under the same label. I think Utada is their only Japanese-English person. So they spoke about her when they thought "oh hey we do have a japanese asian, what's her name?" because he's singing these with different people of different territory...

It doesn't help though, that Utada's vocals absolutely SUCK in this song. That's my opinion though.

Hopefully she'll actually work with him in a song, because his NeYo/Rihanna song is great.