Pearl Jam is celebrating twenty years of work and this past weeked held thier "PJ20" two day festival at Alpine Valley in Wisconsin.

The shows were reportedly full of incredible surprises for PJ fans, including - hold on to your hats - appearances both days by the one and only Chris Cornell for a little Temple of the Dog reunion action.

Wow.

There were also appearances by members of Queens of the Stone Age and The Strokes.

And if things couldn't get any cooler, the final performance Sunday night featured everyone coming on stage for Neil Young's "Rockin' in the Free World".

I repeat: wow.

Also on Sunday, Eddie Vedder debuted a new song. Not sure if this will be a Pearl Jam track or a solo number, but he did come onstage alone for PJ's first encore and told the crowd "I was talking to a friend of mine earlier, John, and I said something, I was just talking and he said, 'That's a pretty good line.' So with all the free time that I had today, I just wrote a little song, and might just try it."

Not exactly sure of the title but check it out!