NOTE: Joel, if you are reading this, and want me to take this video down, please message me or comment and I will gladly remove it.
NOTE 2: As it's a stream rip, this audio has a couple errors in it towards the end, apologies.
This is a new song that Deadmau5 has been working on lately. After uploading a 3 minute preview that he put on his SoundCloud (http://www.youtube.com/watch?v=032FS_qYHhY&hd=1), he decided to change the instrumental of the song. He changed the instrumental to a new progressive house style track that's based off of the song, "Arcadia." (http://www.youtube.com/watch?v=m9aNCaG80AY&hd=1) This is that result.
The singer is Colleen D'Agostino (aka Colleen Moreaux)
This audio is pulled from one of his streams. At one point in the stream, he says "F*ck it, I'm just gonna play it all the way through for you guys." This is the song that followed.
Joel says that when the song is released it will most likely be around 16 minutes long! Expect this to be on his 2014 album.
UPDATE: Joel has finished the final mastered track. It will be his longest song ever (15 minutes and 30 seconds - beating his current longest track, "Hiatus Fantasy": http://www.youtube.com/watch?v=ck4Eri5jTMM&hd=1 He's also going to rename this song "Somewhere Up Here". Therefore, I have no idea what he'll name this song: http://www.youtube.com/watch?v=LWbtDeZNTWY&hd=1 Source: http://www.reddit.com/r/deadmau5/comments/1s5o48/somewhere_up_here/
UPDATE 2: Joel is ditching this track. Instead, he's just gonna release "Somewhere Up Here" (http://www.youtube.com/watch?v=LWbtDeZNTWY&hd=1). Source: https://cahern7.com/share/2014-01-07_14-32-07.png
UPDATE 3: Despite previous comments saying he was going to ditch the track, on January 30th, on a livestream, he works on this track. http://www.youtube.com/watch?v=KGzgxmd5bXo&hd=1
UPDATE 4: Awesome news! This song WILL be released! It'll be on the new album! However, the album version is this song COMBINED with the rock version of Somewhere Up Here (http://www.youtube.com/watch?v=LWbtDeZNTWY&hd=1).
UPDATE 5: Update 4 is a lie (the "final version" is nowhere to be found on the tracklisting. Instead he put the rock version of it on the album): http://i.imgur.com/gymKKE5.png
UPDATE 6: Joel is trying the vocals of this song over a new track: https://www.youtube.com/watch?v=AVyp0PHpR28&hd=1
UPDATE 7: Joel works on this track a little in a livestream: http://www.youtube.com/watch?v=89xbybn9zMw&hd=1 http://www.youtube.com/watch?v=zX8_Y60kO_w&hd=1
UPDATE 8: http://i.imgur.com/XgSNMsT.jpg
UPDATE 9 (BIG NEWS!!!): After years of anticipation, this version of the track is finally getting a release! It will be released as Colleen D'Agostino Ft. Deadmau5 on her new EP. Additionally, the track finally has an official name - "Stay".
Check out the radio edit here: http://soundcloud.com/colleendagostino/stay-feat-deadmau5-radio-edit-1.
Check out the official/final "Drop The Poptart Edit": https://www.youtube.com/watch?v=EfeOr07tTRA
Here's the official album artwork: http://i.imgur.com/BGDdPyk.jpg.
EDIT: 1,000,000 VIEWS! Thanks everyone! Glad I wasn't the only one that fell in love with this track.