Nirvana singer's version of "And I Love Her" will appear in upcoming documentary 'Montage of Heck'
Filmmaker talks about the infamous movie on the rock star couple: "Courtney started defining the film"
HBO offers in-depth look at the upcoming documentary with never-before-seen home movies and family photos
Cobain doc director Brett Morgen describes resurfaced song as "a mind-blowing 12-minute acoustic Cobain unheard track"
Daughter of Courtney Love says Dave Grohl never hit on her