American "Pop Queen" Lady Gaga who's making her movie debut with "A Star is Born" insisted that all songs in the musical drama were performed live, including those by novice musician Bradley Cooper.
"Singing live, there really was no question," Cooper, who co-stars and directs the film, told a news conference on Sunday at the Toronto International Film Festival.
"When we first met, Stefani was very adamant about it," said Cooper, referring to Lady Gaga by her real name, Stefani Germanotta.
"A Star is Born" tells the story of country music singer Jackson Maine (Cooper), who meets, nurtures and falls in love with aspiring musician Ally (Lady Gaga). As Jackson deals with addiction and tinnitus and his own star wanes, Ally's career takes off.
As well as marking Cooper's directorial debut, the film is also the first to showcase his voice, songwriting and musical abilities. The "Silver Linings Playbook" actor has said he took singing and music lessons for six months.
"Preparation was the hardest thing," he said. "Starting to sing and realizing that I really couldn't, starting to learn guitar and piano and realizing I couldn't."
Actor Lady Gaga arrives for the world premiere of 'A Star is Born' at the Toronto International Film Festival (TIFF), Toronto, Canada, September 9, 2018. /VCG Photo
Lady Gaga, known for hits such as "Poker Face," and "Born This Way," made her television acting debut in "American Horror Story: Hotel" winning a Golden Globe in 2016. But taking the lead role in "A Star is Born" was a big leap.
"At the beginning of making this film, we shook hands literally, and he said to me, 'You're an actress'," Gaga said. "And I said to him, 'You're a musician'."
The movie's concert scenes were shot on the stages of some of the world's biggest music festivals, including Coachella in California and Glastonbury in England.
"The opening of the movie, we shot in eight minutes," Cooper said. "Then we went to Glastonbury and we shot for four minutes."
"The music, the songs are a complete character in the movie," he said. "There's not one lyric that's not purposely put there."
"A Star is Born" is the third remake of the original 1937 film. It was remade in 1954 with Judy Garland, and in 1976 with Barbra Streisand.