Disclaimer: All my personal source material is largely in storage, so this may not be the ideal posting. But I can cite my source for this nugget as coming from Skydog: Randy Poe (Author) & Billy S. Gibbons (Foreword); (September 2006)
Note: The below, aside from the quoted piece are largely my own words.
In 1968, The Beatles were killing it, and had just released Hey Jude as a single. 'Round the same time, a still young and fresh Duane Allman was busy as a session guitarist as Muscle Shoals in Alabama where Wilson Pickett, of Mustang Sally fame, had arranged some studio time to record his next album. Despite all his talents, Duane wasn't able to read music. Of course this didn't stop him, and when Wilson had run out of material for the album, Duane slyly suggested doing a cover of Hey Jude, which was still in the charts.
He already knew all the changes, chords and everything, and they set about recording it. As it turns out, it was also the name of the album that Wilson had released from this session.
>...Eric Clapton commented, "I remember hearing [it] and calling either Ahmet Ertegun or Tom Dowd and saying, 'Who's that guitar player?'...To this day, I've never heard better rock guitar playing on an R&B record. It's the best." Pickett commented on the outro that "people were going crazy" and session musician Jimmy Johnson said that the Allman's solo "created Southern rock".