Zac Brown Band were  joined on the 2011 CMA Awards by the legendary Gregg Allman on keyboards for a rendition of 'Georgia on My Mind.'

The emotional performance by the Georgia natives resulted in a standing ovation by the all-star crowd.

The Zac Brown Band are nominated for a host of honors at the 2011 CMA Awards, including Vocal Event of the Year for 'As She's Walking Away' (which features Alan Jackson),Vocal Group of the Year, Album of the Year for 'You Get What You Give' and Single of the Year for 'Colder Weather.'

Allman, a member of the Rock and Roll Hall of Fame and one of the "100 Greatest Singers of All Time" as honored by Rolling Stone, has struggled with a host of health issues in recent years. Although he's been sober since the '90s, his addiction to a variety of substances severely impacted his health. He had a liver transplant in 2010.

The founding member of the Allman Brothers Band still tours with the band and as a solo performer.

Watch Zac Brown Band Perform With Gregg Allman at the 2011 CMA Awards