The two actors who portray Beach Boy Brian Wilson in a film about his troubled life say getting a deeper knowledge of the revered Californian songwriter's music helped their performances nearly as much spending time with the man himself.

"Love and Mercy," which had its world premiere at the Toronto International Film Festival on Sunday, stars Paul Dano and John Cusack as younger and older versions of Wilson, cutting between his creative peak in the 1960s and painful recovery from mental illness, addiction and abuse two decades later.

Wilson's turbulent life is already the stuff of music industry legend. He shot to fame in the early 1960s as the lead songwriter for the Beach Boys, producing hits like "Surfer Girl" that became the soundtrack for an era.

Yet Wilson's ambitions ran deeper. Enthralled by the complexity of the Beatles' "Rubber Soul," he set out to top them. "Love and Mercy" depicts the production of his landmark "Pet Sounds," one of the most highly regarded albums in rock history.

Dano said his performance was guided by the hours of audio still available from those and other sessions, in which Wilson can be heard giving detailed directions to and joking with musicians.

"I just tried to capture his spirit as best as I could. He's such a generous guy. He talks about wanting to make music that will help people heal, that will help people smile," Dano told Reuters.

"Without question, learning to play and sing and listening to the music was the most important, because the most true Brian to me is in 'Pet Sounds.' If you want to know him, you go listen to it."

'PORTRAIT OF THE GENIUS'

Cusack said hearing Wilson's early work, particularly the long unreleased "Smile Sessions," also increased his appreciation for a musician he already revered.

"You get a portrait of the genius at work at the apex of his powers at the time before he kind of went into the ashes," he said.

Cusack portrays Wilson as he recovered from a combination of mental illness and drug use that at one point caused him to retreat into his bedroom for more than two years.

He eventually fell into the hands of psychologist Eugene Landy, played by Paul Giamatti in the film, who went beyond treating him to taking over his business affairs and nearly every aspect of his life. The film covers the clash between Landy and Melinda Ledbetter, whom Wilson eventually married.

Both Wilson, now 72, and his wife cooperated in making the film and attended the premiere in Toronto. When the screening ended, the audience gave the couple a standing ovation.

While "Love and Mercy" covers some of the most traumatic moments in Wilson's life, Dano said the musician told him afterward he was pleased with the work.

"He loved it," said Dano. "And Brian, he's a little unfiltered, so you would know if he didn't. I was so happy to see him. He loved it. And he was thankful. It was beautiful."

(Editing by Mary Milliken and Dan Grebler)