October 3 marks the 20th anniversary of Farm Aid 1998, the 12th installation of Willie Nelson’s benefit for the farmers of America.

The 1998 edition of the socially-conscious festival featured a diverse group of musicians – including Nelson, Phish, Neil Young, John Mellencamp, Steve Earle, Del McCoury Band and Wilco – who all gathered at Tinley Park, Ill.’s Tweeter Center for an evening of environmental education and musical collaboration.

One of the biggest highlights came when Young joined Phish onstage for a rocking version of “Down By the River.” Trey Anastasio, Mike Gordon, Page McConnell and Jon Fishman all groove seamlessly with Young on the Crazy Horse tune, which they stretch and jam into oblivion.

As you watch the video below, pay attention around the 7:30 minute mark. The two guitarists get so into it that Young even loses his hat.

Clearly, Young and the quartet from Vermont are having a blast. So much so that less than a month later, on 10/17/98, Young joined the band once again for a version of “Helpless” during the 12th annual Bridge School benefit at Shoreline Amphitheatre.

Watch Neil Young and Phish perform “Down By the River” below: