"I could have been Britney [Spears]," Blunt said. "I realized that I'm not good at dancing, and I didn't want to be Britney."
Blunt confirmed that she recorded a few songs, including a track called "Ring It Up." The song was written for her by someone who encouraged her music career.
"They said, 'I think you have a nice voice, and I think that you could be a pop star.' I said, 'I can't dance.' They said, 'Don't worry about it. We'll teach you,'" Blunt recalled. "It didn't work. I tried to learn."
Blunt ultimately gave up her pursuit after speaking to Dench, her co-star in a play.
"My first job was with Judi Dench, which was incredible. She was wonderful to me," Blunt said. "I went to her for advice because I was really, really nervous about this career that I didn't know was right for me. She said, 'Oh, no, darling, you can't do both. You can't act and do that.' She talked me out of it."
Blunt performs songs in Into the Woods and Mary Poppins Returns. She is shy about singing but sang an apology to Coldplay frontman Chris Martin on The Ellen DeGeneres Show in January after ignoring his pitch for A Quiet Place Part II.
Blunt will next star in A Quiet Place II, which opens in theaters March 20. On Jimmy Kimmel Live!, Blunt spoofed the movie in the sketch "A Quiet Plane."