John Mayer performed a mash-up of Grateful Dead's classic "Dark Star" and his 2001 solo hit "Your Body Is a Wonderland" at his concert in Chicago on Wednesday.

"I'm not going to set it up - this is going to be the weirdest thing you ever saw in your life and I'm proud to do it," Mayer said from the stage. "I want you to mark it on the set list that this is technically 'Dark Star.' And I'm going from 'Dark Star' into this next song. It's a transition. I want you to mark the transition."

You can see fan-filmed footage of the performance below.

READ MORE: Did Grateful Dead Go Disco on 'Shakedown Street'?

"You know what that just was?" he asked after a few minutes. "And I do this with extreme love for my brothers in the company. With all love and reverence, that was 'Dark Star'/'Your Body Is a Wonderland'/'Dark Star.'" Mayer was referring to Dead & Company, the Grateful Dead spinoff group that recently concluded its farewell tour after eight years of performing.

The Future of Dead & Company

But as several of the band's members have emphasized, they don't plan on fully retiring the group.

"We will play shows — I have to believe that we love this music so much we're gonna play shows — we just are trying to figure out what that looks like for the future," Mayer said earlier this year. "Everyone has it in their hearts to keep playing."

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Gallery Credit: Michael Gallucci

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