Oscar winner aims for pitch imperfect in "Florence Foster Jenkins"

Streep plays the heiress who was convinced of her vocal talents and went on to put on a show at Carnegie Hall in 1944.

"Well it's a great story. It's about a real-life person who lived in the first part of the 20th century in New York, a socialite who gave a lot of money away to the arts, but her dream was to be a singer," Street said at the film's premiere in London on Tuesday night.

"And with the love of her husband, she was able to believe that she was a singer. But she was a true amateur, she did what she did for the pure love of it. And that's sort of what's beautiful about her."

Streep, 66, has sung before in movies including "Mamma Mia" and "Into the Woods", but this role required her to hide her capabilities.

"What was sort of wonderful about her was how close she came to being good, and when it went off, that's when it got sort of glorious and funny," she said.

"But it was the attempt, the sort of yearning for it to be good that is the part that's so joyous for me and was fun to do."

"Florence Foster Jenkins" opens in the UK on May 6 and in U.S. cinemas in August.

Watch Meryl Streep in 'Ricki and the Flash' trailer below: