Lady Gaga and Bradley Cooper Recall the 'Magical' Day They Decided to Make 'A Star Is Born' (Exclusive)

ET talked to the movie star duo at the Toronto International Film Festival.

Pasta dinner and a piano. That's how A Star Is Born came to be.

The remake of the classic film, starring Lady Gaga as well as Bradley Cooper in his directorial debut, has -- from Gaga's haaa-ah-ah-ah-aunting voice in the trailer, the early festival circuit praise it's garnered and the absolute classic Hollywood glamor of the film's press tour -- turned into the most feverishly anticipated movie of 2018.

So, how early did the star pairing know they had something special? Pretty much right away, obviously.

"I actually was performing at a cancer fundraiser for Sean Parker and I sang the song 'La Vie En Rose,' which, not to give it away, but it is in the film, and I sang that song, and the very next day, he wanted to meet me and he came over to my home," Gaga, 32, told ET's Keltie Knight at the Toronto International Film Festival on Sunday. "I opened the door, and the second I looked into his eyes I felt an instant connection to him."

As Gaga explains it, part of the reason the two clicked is their shared cultural upbringing.

"We're both from the east coast, we're both coming from Italian families, I was like 'Are you hungry?' I cooked him up some leftover pasta, and we were eating, and before I knew it, he said 'I would like to sing with you, if that's OK.' And we went to the piano, and I printed out the sheet music for a song that he wanted to sing called 'Midnight Special,'" she shared. "I sat down and started to play, and he began to sing and I just stopped instantly in my tracks, and I looked at him and I said, 'Bradley, you have an incredible voice, you sing from your gut, you sing from your soul, you sing from the nectar of your being.'"

OK... When one of the most powerful vocalists of our time starts throwing around "nectar of your being" after hearing you sing, that's a moment you probably want to hold onto. So Cooper did just that.

"He said, 'Should we film it?' So he filmed it on his iPhone, and we all of a sudden started to sing together, harmonizing and laughing, and looking at each other," Gaga continued. "It was instantaneous, and I knew in this moment that I could make this film with him, and I truly believe that there's no other actor or director in the world that could have played this role or made this film."

"There's no other actor that could play a rock star, he's the only one," Gaga commented, even adding that if Cooper wanted to take on a real-life singing career, he'd be a natural at it. "If he wants to, he can do anything."

Cooper, meanwhile, doesn't share Gaga's view that he'd be cut out for being a singer. But he did reveal that his meeting with her was just as life-affirming as she described it.

"I remember every single moment of it. From the moment she walked down the stairs, it was one of those magical things," the 43-year-old actor told ET.

George Pimentel/Getty Images for TIFF

And for those of us looking on, the way the pair rolled onto the red carpet at the festival was just as magical. Of course, Cooper takes no credit for that, saying, "That's all her, man, I just walked next to her."

A Star Is Born premieres on October 5.

This isn't the first nugget of insight we've gotten into the conception of the movie. Watch the video below for how Cooper convinced Gaga to go makeup free in the film.