Meryl Streep said she gave up singing early on and proceeded to ruin her voice with "smoking, drinking and debauchery".
Her latest role sees her playing wealthy socialite and opera singer Florence Foster Jenkins, who became renowned for her lack of musical talent.
Triple Oscar winner Meryl said she feels like she is a "B, B+ singer" who is "very aware of her limitations".
She told Radio Times: "Much as I would have liked to be a good singer after I began studying opera as a child, I gave it up very early and sort of ruined my voice with smoking, drinking and debauchery."
Bridget Jones favourite Hugh Grant stars alongside her, playing Florence's manager and partner, St Clair Bayfield.
St Clair and Florence were a couple, albeit a platonic one, he explains.
He said: "It's a very strange relationship, in which you wonder, 'Is this guy in it for himself? Or is this real love? I think that was one of the things I liked about the script very much, it is a very strange, unorthodox shape of love that is being celebrated, and I'm all for that."