Julio Iglesias

Johnny Carson Willie Nelson

Flashback: Johnny Carson Hilariously Impersonates Willie Nelson on 'The Tonight Show'

George Strait Sing One With Willie

Flashback: George Strait and Willie Nelson Team Up For 'Sing One With Willie'

To All the Girls I've Loved Before

'To All the Girls I've Loved Before': The Story Behind the Classic Duet

Willie Nelson Duets

11 of the Best Willie Nelson Duets and Collaborations