"How does it feel?" is one way by which to measure a movie. But if you've seen "A Complete Unknown," the Bob Dylan biopic that opened on Christmas Day, you may have left the theater singing to yourself (to the tune of "Like a Rolling Stone"): How much is reeeaaallll?

"A Complete Unknown" director James Mangold and Edward Norton (as Pete Seeger) weigh in on what's fact and what's fiction in the Bob Dylan movie.

Timothée Chalamet, Edward Norton and other stars of Bob Dylan film "A Complete Unknown" spent months learning to sing and play to re-create the past.