Grateful Dead, John Mayer Set to Rock Madison Square Garden as 'Dead & Company'

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Just when you thought the Grateful Dead was done… they've added John Mayer to the mix?! 

After the band's Fare Thee Well concert series wrapped on July 6 in Chicago, promoters announced today that surviving members Mickey Hart, Bill Kreutzmann and Bob Weir will take the stage on Halloween night at Madison Square Garden in New York City with none other than John Mayer.

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Why does this make so much sense? Mayer, with Katy Perry in tow, was recently in attendance during the second night of the three-day Fare Thee Well engagement. The "Gravity" singer-songwriter isn't just a casual fan, either. Having seen the Grateful Dead a total of five times, according to Billboard, Mayer is a hardcore Deadhead.

“I deeply love the Dead’s music, and it has inspired me in ways I never imagined. To help carry this music is the opportunity and the honor of a lifetime,” Mayer, 37, said in a statement to ET.

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What else makes sense? The name of their newly formed band: Dead & Company. If you're one of the biggest rock bands in music history, your company might as well be someone who loves and respects the genre as much as Mayer. When Oct. 31 finally rolls around, expect the shows to include two sets of music mostly culled from the Dead's legendary catalog, says promoters.

"We're not done with these songs and they're not done with us,” said Weir, the Dead's guitarist. “We're gonna take these old friends on some new adventures.”

Count us (and, obviously, Mayer) in for the ride!

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Now: Is John Mayer an egomaniac? Find out what he thinks of himself in the video below.