It looks like a reworked version of Lady Gaga's 'Do What U Want' featuring the dulcet tones of Christina Aguilera will be released on January 1 2014.
That image above is apparently the artwork and the song has been listed on Amazon so it must be true.
It's not clear if this is just a recording of the live version they did on The Voice a few weeks ago, or the result of some studio time, but we'll find out soon enough.