By Bob Mezan

NEW YORK (Reuters) - Meryl Streep has showcased her musical talents in several films, but her abilities take a purposeful turn for the worse in "Florence Foster Jenkins."

The triple Oscar-winner portrays the real-life title character, a World War Two-era New York socialite whose passion for music far outweighed her singing skills.

"Yeah, she aimed high," said Streep, who had voice lessons while a teenager.

"She picked the most difficult arias in the coloratura canon, absolutely. And she screwed it up every time, but she knew them. She knew how they should be done and she really did try her very best. I discovered when listening to her recordings that it wasn't how bad it was, it was how close it came to being almost good and that's what made you want as an audience to root for her and then be disappointed."

The movie, opening in U.S. movie theaters on Friday, follows Jenkins around 1944 as, at age 76, she prepares for her first big public performance at a sold-out Carnegie Hall.

Weak from a nearly half-decade battle with syphilis, Jenkins is determined to deliver her best at the concert, but is blindly unaware that people's interest in her is due to her lack of skill. Her philandering husband, played by Hugh Grant, has been hiding the truth from her, allowing his wife to think she is an operatic wonder.

"In all the characters I've played, I don't think, except maybe for (American chef) Julia Child, I've ever played anybody with so much joie de vivre... She just soldiered on in spite of it all and that was very touching to me," Streep said.

Grant said that, unbeknown to Streep, people on the film set had a "bad-ometer" scale on which to judge the actress's performance.

"Sometimes she would do bad singing that was like 2 out of 10 bad and sometimes she would crank it up to like 12, and those were very difficult to cope with, particularly if I was having to do some very serious, stern, protective scene at the same time," said Grant.

The film is an ode to following your passion no matter what people think of it.

For Streep, 67, there is one part of her life she powers through, even though she might be lackluster.

"I'm not that good of a cook, but I'm obliged to do it at my house. Nobody else does."

(Reporting by Bob Mezan; Editing by Jill Serjeant and David Gregorio)