Rachel Zegler‘s rise from high school student to “West Side Story” star is well known.

But the film’s casting director Cindy Tolan revealed the search that went into finding Ariana DeBose and David Alvarez as Anita and Bernardo, with DeBose initially declining a chance to audition and Alvarez, who had retired from acting, uncontactable.

Speaking to the press backstage after picking up a BAFTA award for casting for “West Side Story,” Tolan revealed that she was hired a year and a half early to pin down the five leads. “Because essentially, Steven [Spielberg] said, if we can’t find them, then we’re not going to make this movie. And so in the first three weeks of working and searching, we got Rachel Zegler’s tape […] that went that went viral [on social media].”

“You always think it’s going to be Maria, you always think Maria is going to take the longest. And as soon as you watch [Zegler‘s tape] it’s excitement but also immediately, as a casting director, it’s utter relief, because then you’re like, ‘Okay, great. We got that. There’s the anchor. Now we just have to look for all the other ones.'”

First, she had to pin down DeBose, who also won a BAFTA for best supporting actress for her role in the musical at the ceremony in London on Sunday evening. “I tried to get Ariana DeBose to audition four times,” Tolan revealed. “She would not come in. She was busy working on Broadway, she was rehearsing and she was in previews for ‘Summer: The Donna Summer Show.’ And she’s just like, ‘I’m never going to get this. I’m not going in.'”

“Finally, I picked up the phone and I called her directly,” Tolan recalled. “And I said Ariana — it was 10.30 at night, we were having a big day the next day and we were seeing a couple of other Anitas — and I’m just like, ‘I need you to come in. I need you to come to Brooklyn, and I need you to meet Steven Spielberg.'”

“And she said, Cindy, it’s so far. I’m in rehearsal. I’m in previews, you’re giving me 20 pages of sides. I can’t audition and I can’t read – this is Tony Kushner’s script. I’m not going to be able to do it.”

Eventually however, DeBose agreed to come in and sing and dance in her audition. “So then she came and she sang and she danced,” said Tolan. “And then Steven said, ‘Great. Will you now read for me?’ And she said, ‘No. I explained to Cindy that I won’t read because I just got these pages last night, but I will sing and dance.’ And then he just said ‘Will you come back and read?’ And she said ‘Yes of course.'”

Equally challenging was casting Anita’s partner Bernardo. After seeing a number of actors, Tolan remembered David Alvarez, who had been one of three actors to play Billy Elliot in the U.S. adaptation of the musical, for which he won a Tony Award at the age of 14.

“But he dropped out of the business and he went into the army and he didn’t have an agent and we couldn’t find him,” said Tolan. “We had seen the other two Billy Elliots [for auditions] and I’m like, ‘Well where’s David Alvarez?'”

“So we started tracking him and looking for him and reaching out to him and DMing him on social media. And he was backpacking in Mexico for two weeks with no cell phone service. So he finally gets back to to Ohio, which is where he was living. He was like, ‘Okay, I’ll just respond.’ [We] got his tape and within two days of him responding he was on a plane to meet Steven Spielberg the next week.”

Tolan also addressed a question about the controversy over the age difference between Zegler and her on-screen love Ansel Elgort, who in real life is seven years older than the actress. “You know, I didn’t even hear this controversy, this is the first time,” Toland said. “There’s lots of controversy, but not that.”

“So I [didn’t] really ever clock that that was a problem whatsoever. To me it never – because Ansel is in his early 20s and at the time that we started shooting, Rachel must have been 18. So to me, that wasn’t a very big age gap. And also, I think Tony is not written as a specific age. But Maria is. And also going back to Romeo and Juliet and I’m thinking, ‘meh.’ No, I don’t think that there’s any problem with it whatsoever.”