Madonna continues to keep fans guessing as to what big-named collaborators might appear on her next album -- due in 2015 -- thanks to her numerous posts on Instagram. The shutterbug diva has taken a shine to the photo-sharing service this year, uploading numerous images of potential pairings, but which artists will make the cut?

Billboard looked to Madonna's Instagram to determine who her likely co-conspirators will be on the follow-up to 2012's MDNA. Let's examine the candidates, in order of their likelihood to appear on her next album.

- Keith Caulfield