Jonny Owen has said he was under an immense amount of pressure from the rest of the Svengali team to sign Vicky McClure in a lead role.
The director, who also plays the main part of Dixie in the film about a man who takes on managing a new band despite having no experience, said he was desperate to get the This Is England star signed up to play his girlfriend.
He said: "When she agreed to the part I was happy then, I didn't really care who else did it, I was like, 'I've got Vicky McClure', because I wanted that strong female lead."
But Jonny admitted he was nervous because everyone else in the office had told him he had no chance of getting the Bafta winner and Broadchurch actress to do an indie film.
He said: "She'd seen the script, liked the virals and was interested in talking to me. So everybody in the office was going, 'Once Jonny speaks to her, he'll nail it,' and I was going, 'That's pressure, now. What if I mess it up?'
"So I was like, 'I've got to try and be really nice.' I didn't know what she was going to be like. I'd heard her on the radio so I had an idea, but within two minutes, she went, 'I'm going to do it.' I was like, 'Get in!'."
Vicky said of their phone call: "It was one of those phone calls where you kind of start off really polite and you kind of repeat yourself... and before you know it an hour had passed and we'd covered life."
Jonny added: "Do you remember the end of the phone call? I said, 'One of the most important messages of the film is that love is the most important thing,' and she went, 'I agree'."
Vicky laughed: "I do!"
Svengali is released in cinemas on March 21.