One of Rock's busiest men has recruited several fine guest musicians to add bonus material to one of his groups next albums.  Allman Brothers Band member and festival organizer (Mountain Jam and Peach) Warren Haynes has announced that the 4th studio album from his other group, Gov't Mule, will include alternate versions of the eleven tracks the Mule does on the disc recorded by Steve Winwood, Dr. John, Elvis Costello, Ben Harper, Dave Matthews, Grace Potter, Toots Hibbert of Toots & The Maytals, Glenn Hughes, Myles Kennedy and others. Shout! is due for a September 24 release.  Haynes is clearly excited by what he's heard, saying, 'Their performances bring new ideas, energy and sometimes even different meanings to every number.'  
The concept of guest versions of songs on the album was sparked when Haynes sought some tips from Elvis Costello on how to mic and record one of the tracks. Funny Little Tragedy.  He says Costello gave him an account of his approach to recording the vocals on all of his albums, including the recommendation that vocals to some songs sound better when they are recorded on relatively entry level microphones.  Reviewing the extensive notes Costello sent, Haynes started thinking about what the song would sound like if Costello recorded it and asked Elvis if he'd do it. With one in the bag, Haynes started matching-up the other tracks on the album with artists he thought would be fun to have interpret.
Here's the lineup on the bonus disc (all titles also done by Gov't Mule on the album):

World Boss - Ben Harper
Funny Little Tragedy - Elvis Costello
Stoop So Low - Dr. John
Captured - Jim James

Whisper In Your Soul - Grace Potter

Scared To Live - Toots Hibbert

No Reward - Glenn Hughes

Bring On The Music - Ty Taylor

Forsaken Savior - Dave Matthews

Got Done Wise - Myles Kennedy

When The World Gets Small - Steve Winwood