That Paul McCartney returned to the "Get Back" last night at Lollapalooza wasn't the surprise; it was who he brought out on stage.

In the video above, McCartney invites soul-shouter Brittany Howard from Alabama Shakes to add an R&B twist to the Beatles favorite, creating a highlight in what became a 31-song set at Chicago's Grant Park on July 31.

Howard took over George Harrison's familiar guitar lead, then returned – after Paul "Wix" Wickens grooved through Billy Preston's original keyboard run – to sing a raucous verse of her own. Later, she traded licks with long-time McCartney guitarist Brian Ray.

As "Get Back" seemed to conclude, McCartney asked, "Brittany, you want to get back?" She replied, "Let's get on back home, Paul." McCartney asked again. "You know I'm trying to get back on home, Paul!" Howard cried. "Me, too, baby," McCartney added, with a huge smile – and the group returned to the song's familiar loping groove for another fun sing-along encore.

McCartney announced earlier this week plans to reissue two early '80s solo projects, 1982's Tug of War and 1983's Pipes of Peace – both of which found him collaborating with Beatles-era co-horts Ringo Starr and George Martin. This expansive Out There tour has also included his first visit to South Korea.

Alabama Shakes had appeared earlier in the day at Lollapalooza; Metallica is set to play tonight.

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