Will says he also has unreleased Rihanna and Nicole Scherzinger tracks.
"I got a hard drive full of songs that just sit there and we could go through them," will told Digital Spy. There's Nicole Scherzinger folders, there's Britney folders, there's Rihanna folders, Beyoncé folders - just songs."
Will says when he works with an artist, they write and record a bunch of different songs, "and to get one song you have to record seven. So those other six are actually really good. Maybe there's two of them that are good, maybe there's one lingering one that just needs some touching up."
"So you just go through the hard drive. There's Michael Jackson folders, there's Whitney Houston folders, there's a Mariah Carey folder."
Will adds he gets asked to produce songs for artists when they're looking for something monstrous.
"Because I get called to - I'm like the person they call. 'We want something different, we're looking for something different, we need an international song.' So they always call. Me and my squad of writers. So yeah. They're just going to sit there on my hard drive. Somebody has to go through them."
Part of me desperately wants to hear these leftover tracks, the other part has flashbacks of "It Should Be Easy" off Britney Jean and is perfectly fine with the rest never surfacing.