The Cranes in the Sky singer invited MCDonald to collaborate on a rendition of the rockers' What a Fool Believes song at the bash, and Beyonce's sister took to Instagram after the gig to share her joy about the unexpected performance.

Posting a short clip of their appearance, Solange wrote, "Anyone who knows me knows that the Doobie Brothers are my musical/harmonic/chord change hero's (sic) and that I listen to It Keeps You Running everyday for encouragement. that was fun Michael."

MCDonald, 65, performed as part of the Doobie Brothers from 1976 until 1982, and co-wrote What a Fool Believes with Kenny Loggins.

The Okeechobee line-up also featured Kings of Leon, Usher & The Roots, The Lumineers, and Wiz Khalifa.