The Asleep At The Wheel musician's birthday show has become a star-studded staple at the Austin, Texas festival and raises funds for the Health Alliance for Austin Musicians (HAAM).

This year (17), Benson was joined by the likes of The Avett Brothers, Randy Rogers, Charlie Sexton and Shannon MCNally, and Marcia Ball, among others, but it was Nelson's appearance which really whipped the crowd into a frenzy.

Willie, who recently had to cancel some concerts as he battled a cold, delivered renditions of songs including Whiskey River and his classic On the Road Again, and teamed up with his longtime pal Benson for a cover of Townes Van Zandt's Pancho & Lefty.

Benson, who actually turns 66 on Thursday (16Mar17), is a co-founder and board member of the HAAM organisation, for which he has raised $4.9 million (£4 million) since 2005, reports Billboard.com.