Joaquin Phoenix and Reese Witherspoon

8 of 10
"For me," Joaquin says, "it's not about acting. It's not pretending. It's about genuinely trying to go through emotions and feel things." Joaquin and Reese spent six months prepping for their roles, and got to know each other well over the course of the film.

What most surprised Reese about working with Joaquin? "He's funny!" Reese says. "I said, 'Why don't you do some comedies with me?' He [joked], 'Because they're all bad.' He's really funny and he's got a big heart. He's a good guy and he's a really good friend."

"It was really inspiring to see an actor so dedicated to a role. He would go to work and work all day in Johnny's voice and go home and study at night and watch videotapes or play with the band and practice. He never said, 'Okay, I'm good; I'm done.' He always was working on it."