The day Meryl Streep became the world's worst singer - with a little help from Hugh Grant

Florence wasn’t just bad – she was truly terrible. But instead of being ridiculed, her awful arias became the stuff of legend. Her recordings (also self-funded), one of which was called The Glory of the Human Voice, became a cult joke. David Bowie was apparently a big fan.

Now, her operatic ambition is being celebrated by Stephen Frears (The Queen), with triple Oscar winner Meryl Streep as Florence and Hugh Grant her partner and manager, St Clair Bayfield. Streep, who has a good voice (watch Mamma Mia!), prepared with vocal coach Arthur Levy. “I went to him twice a week, and broke his spirit,” the actress smiles. “I knew we had something when the accompanist, who played like this [does a serious face], would giggle periodically.

“I feel like I’m a B, B+ singer – I’m very well aware of my limitations. 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,” she laughs. Luckily, that only went to help and not hinder her performance.

https://www.youtube.com/watch?v=HszfdNS0JSc

Grant knew that his co-star had captured the awfulness of Florence’s voice – once described as a “cacophony of squawks and screeches” – at the first script read-through.

“All read-throughs are tense,” he explains. “But this one was a highly wrought occasion. I was thinking about how I had to actually act in front of Meryl Streep! On top of that, Meryl was quite tense because she was going to finally show everyone what she was going to do. Thank God, it was genuinely side-splittingly funny and no one had to do fake laughter.”

On set, it was also hard to keep a straight face. Streep wore a padded suit and festooned her ample body in a rainbow of mismatched colours, in Florence’s flamboyant style.

“What she put on was part of her celebration of being alive. By the end of the film, just as I lost my objectivity about how I sounded – I thought I sounded good – I looked in the mirror and thought I looked good. I completely lost it! I said to my husband, ‘It’s too bad we don’t wear dresses like this any more.’ He said, ‘Are you insane?’"

The giggles would often get the better of Streep. “I’m very bad at not laughing. Yes, you’re concentrating on what you’re doing, but at the same time you’re alive to the fact that it’s ridiculous.”

https://www.youtube.com/watch?v=ptTvko32UVg

But below the grandiose surface, Florence Foster Jennings was a woman who’d been dealt some cruel blows. Born in Pennsylvania in 1868, Florence was a piano prodigy as a child but her ambitions were dashed by her father’s refusal to fund her studies abroad. With her hopes in tatters, she eloped to Philadelphia with Dr Frank Thornton Jenkins, but rumour has it that the marriage ended after Florence found she had contracted syphilis from him.

Back in New York, she inherited a fortune following her father’s death and met Bayfield, the son of an English country parson. Together, they staged tableaux vivants starring Florence, for private audiences.

“She fell for his English charms and they became a couple, albeit a platonic one,” says Grant. “He protected her from knowing how bad she was, organising the audiences so that they were all people who supported her. He kept the bad reviewers at bay, and slipped a bob or two to the others to be nice.”

Despite caring deeply for her, Bayfield never had a sexual relationship with Florence, the film suggests, because of her disease. “Bayfield lived this double life,” says Grant, “where he was an incredibly loyal husband, but also had this other woman living in a flat nearby. But, as he says in the film, ‘Love takes many forms.’ I think that is perfectly possible – it didn’t affect his love for Florence.

“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.”

Florence Foster Jenkins is in cinemas now