The new biopic “Love & Mercy” is unabashedly candid about discussing mental illness. Following the story of Beach Boys singer and songwriter Brian Wilson, the movie is centered on the pop star’s struggle with schizoaffective disorder. John Cusack and Paul Dano play Wilson in his earlier to later years.

At the film's South by Southwest press panel in March, Brian Wilson, John Cusack and director Bill Pohland discussed how they prepared to depict Wilson’s life story.

Pohland revealed the casting choice of Cusack, 48, and Dano, 30, was very purposeful. “When we took a fresh look at the script, the idea was to intertwine these two periods of Brian’s life, the ‘Pet Sounds’ era and the '80s, when he was under the influence of Dr. Landy,” he said in reference to Wilson’s shady psychologist, played by Paul Giamatti in the movie. Pohland said he thought it was necessary to cast two different actors to play Wilson in view of the two different eras.

Cusack said that “Melinda [Wilson’s wife] sent me a picture of Brian’s face and my face back when she met him. We actually do look a little bit alike,” he said, laughing. In preparation for the role, the actor said he was given close access to the Wilsons to observe their relationship. “I was invited to have dinner with them. I would go to his house, his music room,” said Cusack. “I wanted to greedily take as much time, but I didn’t want to impose. They were so open with themselves and their lives.”

A well-known music fan, Cusack spent even more time absorbing Wilson’s catalog of work. “What I found so helpful was the ‘Pet’ sessions and the ‘Smile’ sessions. Those albums [are] where you can hear the maestro at work,” he said. “You can hear him creating these sounds which came to define pop music for the next 30, 40, 50 years. I tuned into him through his music.”

“At the end of the day, I was very nervous,” revealed Cusack. “People I was most nervous about seeing it [the movie] were Brian and Melinda, his close friends and his band members.” But he need not have worried, as director Pohland’s approach presented Wilson’s story as unfinished for good reason. Cusack said having two actors play the role meant that “no one actor and no one story can encompass this man’s life.”

Wilson appreciated the closeness that “Love & Mercy” captured with its actors. He even complimented John Cusack and co-star Elizabeth Banks, who plays Wilson’s wife Melinda in the movie, for their portrayal of the couple’s relationship. “John and Elizabeth appear to be in love with each other, although they were playing Melinda and me.”

“It’s a funny story to tell,” Wilson added. “But it’s gotta be told.”

 “Love & Mercy” opens in theaters June 5.