MadonnaTribe has an exciting and esclusive update on the new Madonna album at less than one month from its March 26 release.

You've just read it in this news' title, the MDNA tracklisting welcomes a track called "Best Friend".
"Best Friend" is a brand new song co-produced by Benny Benassi and it will be exclusive to the Deluxe Edition of the new record.
And there is more to report, first of all the news that the Deluxe Edition is confirmed to have 17 tracks - but only one is a remix, four extra tracks are all brand new songs! 
As you already know MDNA will be published in two different formats. The Standard edition is confirmed to include 12 tracks, 4 more new songs and the "Party Rock Remix" of Give Me All Your Luvin' will be exclusive to the Deluxe Edition.
The physical release of the "MDNA" Deluxe Edition will be a 2 CD set. Disc One will be the same of the Standard edition, and the bonus tracks will be available on Disc Two.
Overall, 5 songs in the new album are produced by William Orbit, and 7 tracks are signed by Martin Solveig.
Benny and Alle Benassi were know as the contributors of two songs, but "Best Friend" brings their share up to 3.
The last song in the lot is produced by Hardy "Indiigo" Muanza. And Madonna, of course.
There have been small tweaks in both the song titles and the tracklist, the latter does not appear exactly as the one listed in the pre-order page on iTunes. "Girl Gone Wild" is now listed with the new title, but more importantly there has been a swap between two songs in the Standard and Deluxe edition.
"B-day Song" will now be exclusive to the Deluxe Edition. Please note that the song does include a featuring by "M.I.A.".
On the other hand, "Love Spent" leaves the tracklist of the Deluxe Edition to join that of the Standard release.
The tracklist is still considered subject to change as manufacturing of the physical release has not started yet, leaving a window open to last minute changes.

Thanks to MadonnaTribe!