TORONTO - Montreal producer Martin Bolduc was in Las Vegas in June 2006 when got a phone call from Paul McCartney's publicist, telling him the former Beatle was available for an interview.

It was an opportunity that Bolduc and Montreal director Adrian Wills had been praying for during the shooting of "All Together Now," a documentary on the making of Cirque du Soleil's celebrated Beatles-inspired Las Vegas show "Love."

The filmmakers were in different cities, they weren't expecting the interview and they had little time to prepare. But as Bolduc puts it - if an ex-Beatle says go, "you've got to be ready."

"The PR agent ... for Paul McCartney called me up to say, 'Hey, you want an interview with Paul McCartney? It's tomorrow morning, 10 o'clock,' or something like that, and I'm in Vegas ... Adrian is in Montreal, so I called him up, I said, 'You're on a red-eye flight tonight, you're coming to Vegas,"' Bolduc said Wednesday in an interview ahead of the Hot Docs documentary festival, where the film is having its world premiere.

"It was literally, (Wills) got off the plane, got in a taxi, went to the Mirage Hotel, in the room, set up the interview and guess what? We forgot to put the tape in the machine! So we were running all over the place to get the tape but that was that kind of adventure that happened with McCartney."

Things worked out and Wills was able to sit down for an intimate chat with McCartney for an hour. He also scored interviews with Ringo Starr, Beatles producer Sir George Martin (sometimes referred to as "the fifth Beatle") and his son, Giles, as well as Beatles widows Olivia Harrison and Yoko Ono.

In addition to those interviews, the film -- a co-production of the Beatles company Apple Corps Ltd. and Cirque du Soleil Images -- also includes a behind-the-scenes look at the making of "Love," as well as a glimpse at the process of remastering Beatles songs for the show.

"I still have shivers every time I see it," said Bolduc, who works for Cirque du Soleil Images. "It brings back this kind of memory, like, having the privilege to be there."

The film shows the input McCartney, Starr, Ono and Harrison had in the Cirque production, and the reactions they and their family had at the opening night of "Love" at the Mirage Hotel in July 2006.

Also highlighted is the struggle the "Love" creators -- including director Dominic Champagne and Cirque du Soleil founder Guy Laliberte -- faced in trying to transform the Beatles' career into an acrobatic show while satisfying the interests of all parties. Yoko Ono and Olivia Harrison weren't shy in expressing their opinions during rehearsals -- at one point Ono calls the "Come Together" sequence "sleazy" -- and McCartney needed assurances that the show was going to be good.

Wills says they didn't feel such pressure while making the film, though.

"With a project like this, you'd think that the doors would've been open to us and we would've gone in and been sort of heralded - that didn't happen. And then you would think that they'd be constantly checking our material to see what we'd been getting -- that didn't happen either because the doors weren't open to us," he said.

"We presented (the film) to Apple and said, 'This is what we think it is, these are the themes, this is the film' ... and they were happy ... for a company that big and that known for control, they were really quite accepting of us and didn't censor us."

Wills got the green light to direct the piece in December 2005. He was initially asked to do a one-hour TV show on the making of "Love," but after capturing so much raw emotion between the Fab Four's family members and their interactions with the cast, it was clear it needed to be made into a feature-length documentary.

"The father and son theme and the theme of family, I really think that plays through a lot because you've got that with George Harrison's son, Dhani coming, and you can see that feeling that he has towards his father," said Wills, who has directed a variety of film and TV pieces.

"We knew it was going to be an interesting story. I don't know if we knew it was going to be as raw and emotional as it became."