It’s funny that this iconic Johnny Cash song, his first #1 hit and the one that inspired the title of the celebrated biopic, was written not about June Cash but Johnny’s first wife, Vivian.
I guess he didn’t find it so easy to be true after he met June.
I keep my eyes wide open all the time
I keep the ends out for the tie that binds
Because you’re mine, I walk the line
I find it very, very easy to be true
I find myself alone when each day is through
Yes, I’ll admit that I’m a fool for you
Because you’re mine, I walk the line
As sure as night is dark and day is light
I keep you on my mind both day and night
And happiness I’ve known proves it’s right
Because you’re mine, I walk the line
You’ve got a way to keep me on your side
You give me cause for love that I can’t hide
For you, I know I’d even try to turn the tide
Because you’re mine, I walk the line
I keep a close watch on this heart of mine
I keep my eyes wide open all the time
I keep the ends out for the tie that binds
Because you’re mine, I walk the line
Meet Me In Montauk 
I don’t think they even made that fact known in the biopic. Meanwhile, quite the picture you found!😀