88-year-old country legend Willie Nelson is releasing Letters to America, a new book, on June 29. A collection of what is described as "his most intimate thoughts and stories," it follows his 2015-released memoir, It's A Long Story. Recently, while promoting the new collection on Jimmy Fallon's late-night talk program, the "Red Headed Stranger" also told another story: this one, regarding how his beloved 1980 single "On The Road Again" was developed.

Impressively, the story is rather simple, as the iconic singer-songwriter recalls that the idea for the song developed while he was on a plane with Syndey Pollack and Jerry Schatzburg, the directors of The Honeysuckle Rose, the 1980-released film in which he starred. Schatzburg needed an original song for the movie. "Well what do you want it to be about?" Nelson asked. Schatzburg said, "Well, something about being on the road." Nelson responded, "How about something like 'On the road again, I can't wait to get on the road again?'"

In a 2015 interview, Nelson also noted he wrote the song on the back of an air sickness bag, adding that once they felt the idea was "great," they asked, "What’s the melody?” He replied, “I don’t know yet.”

Nelson continues his press tour for Letters to America with an appearance via Hunter Kelly's 92nd Street Y interview series on June 29 at 7 pm ET/6 pm CT, for $40 (price includes book) in which, via a press release, it's noted the duo will discuss Nelson's "triumphs and hard times, his passions, his humanitarian work, genre-crossing music and uncommon stylistic ease in country, blues, gospel, jazz and the American songbook."