TORONTO – Robert Redford has co-starred with some of the biggest legends of the silver screen: Meryl Streep! Glenn Close! Jane Fonda!

But it’s acting newcomer Jackie Evancho who recently impressed the “Out of Africa” heart-throb.

“It was just pure joy,” Redford says of working with the singing prodigy on his new film “The Company You Keep.”

The film sees Redford juggle directing duties and a starring turn as Jim Grant, a small-town lawyer and single father whose world is shattered when a young journalist (Shia LaBeouf) discovers his past as a 1970s radical wanted by the law.

The finding sends Grant on the run in search of his ex-lover Mimi (Julie Christie) who holds the key to the long-ago crime and still holds fast to her antiwar convictions.

While many actors would clamour to work with Redford — who won an Oscar for his 1980 directorial debut, “Ordinary People” — Christie needed some cajoling.

Redford, 76, said he understood her reluctance, noting he repeatedly turned down the 1973 weeper “The Way We Were” because he didn’t want to be a “a Ken doll to Barbra Streisand.”

Said the actor: “That resistance, dragging you into something you know you want to do and have to do but you fight it is kind of a weird thing that I understand, so therefore I endured (her resistance). She made it really rough.”

Ultimately, Christie agreed to join a blue-chip cast that also includes Richard Jenkins, Anna Kendrick, Susan Sarandon, Chris Cooper and Nick Nolte.

Still, as the cameras were nearly ready to roll on “The Company You Keep,” one piece of the ensemble remained missing.

Redford — whose last directorial effort was the 2010 period piece “The Conspirator” — struggled mightily to find a suitable actress to play his daughter.

“I have a big thing about child actors, and that is I have an aversion to child actors who ‘act’ as opposed to child actors who can be natural, who can be real,” a rumpled-looking Redford said during a Sunday morning interview at last September’s Toronto International Film Festival.

“Scarlett Johansson was a kid when we did ‘The Horse Whisperer’ and I was very concerned if a child looked like they were acting it would be like fingernails on a blackboard.”

Redford said he had to cast the new film on a very tight budget and that deadlines were looming as his search for a young co-star continued.

He interviewed various child actors (“mostly their mothers, who seemed to be auditioning for something themselves,” he said with a laugh) but was unable to find someone who could improvise with him.

“I felt that since this character had to be nine or 10 years old, there had to be a sense of play that had to be really real and my guess was that it would be achieved by improvising,” he said.

Particularly dejected about the process one night, he headed back to his hotel in Vancouver, where “The Company You Keep” was shot.

“So I’m depressed and I go back to my room and I do something I don’t usually do and that’s surf.

“I’m sitting there all depressed, just drinking and surfing and drinking,” he said with a laugh.

“And suddenly I’m skipping across these channels and there’s this angelic face, this golden-haired angelic face … singing. And there’s a closeup and I think: ‘Who is that?’ and she was singing Puccini’s opera.”

That girl was Evancho, whose soaring voice wowed TV audiences on “America’s Got Talent” and caught the ear of uber-producer David Foster. She’s since released a hit Christmas CD, done PBS specials and performed for Oprah Winfrey and U.S. President Barack Obama.

But could she act? It didn’t initially appear so, said Redford.

After seeing her on TV, he sent out the word that he’d like to get an audition tape of the singing sensation.

“(The tape) was horrible because she didn’t know what was going on and I said: ‘I don’t care and, my gut says (to cast her). So I cast her,’” Redford recalled.

Days later, the pint-sized prodigy was on a movie set trading improvised lines with a screen icon.

And Redford loved every minute of it.

“She was not affected, she played with me, I would kid around, she’d kid around with me,” he said. “To me, that’s an incredible story how that happened.”

“The Company You Keep” opens Friday in Toronto, Vancouver and Montreal.