The singer-songwriter-producer previously told the Guardian that he was "so stoked" to be contributing songs to Britney's forthcoming album, but none of his tracks made the final cut. Now, two previously unheard demos have made their way on to the Internet -- and they're super moody. Listen below.
Spears' finished album ultimately featured contributions from longtime collaborator Dr. Luke, as well as David Guetta, Sia, Diplo and Katy Perry. It was executive produced by will.i.am.