So the Christina Aguilera songs you wrote—for the record, how many will there be?
There are four of them. I think they’re called “I Am”—I called it “Lullaby” but she’s given it another name. But I think it’s called, um—[she starts singing]—oh, “All I Need”! And it’s “All I Need,” “You Lost Me,” “I Am” and something like “Stronger.” But I don’t think she called it “Stronger” in the end. That’s just what we called it. We just call it something while it’s in the working process and then she gives it it’s name. There are some where it totally lends itself to its name and there are others where it’s just like, “No, we had a song called ‘Fighter’ so we don’t want a song called ‘Stronger.’” But they’re all on there. She’s pretty awesome. It was pretty crazy when she sang at me for the first time.

Were there any songs you two recorded that didn’t make it on the album?
No, just those four songs. Then we did another one for her movie with Cher. So it’s been a really good collaboration, actually. We really got along great. We didn’t bin anything, which was good.

Source: Idolator