In 'The Iron Lady,' Streep demonstrates the art of embodying someone else

In The Iron Lady, opening Friday, Meryl Streep is Margaret Thatcher. Not only does the actress - renowned for her command of accents - get the combative cadences of the former British prime minister just right, she nails the gestures, the comportment, too.

Certain to be nominated for a best-actress Oscar, Streep's performance - like her Julia Child, her Lindy Chamberlain ("the dingo ate my baby") - goes beyond mimicry to become art. Streep transforms.

How exactly does she do it?

"Meryl's powers of observation - they're off the charts," says Tovah Feldshuh, a four-time Tony Award nominee now appearing as Madame Rose in the Bristol Riverside Theatre's Gypsy. Feldshuh has played real-life figures Sarah Bernhardt, Katharine Hepburn, Diana Vreeland, and Golda Meir. She says research is key, but then you must "imbibe the virtues and flaws of that person, and discover the 'why.' "

As for Streep's Thatcher, Feldshuh says to look at the actress' lips. "That's not the way Meryl holds her mouth. . . . Just compare her physical aspect as Julia Child to her Margaret Thatcher - it's about beingness. . . . This is an extraordinary ability, an ability that those of us who aspire to be transformational actors want."

Historian John Campbell, whose Thatcher biography served as the source for The Iron Lady screenplay, was awed by Streep's work. The film, directed by Phyllida Lloyd, tracks Thatcher in old age - a widow, afflicted with dementia - and flashes back to key points in her life.

"As a British person who lived through Thatcher's prime ministership, it is uncanny to see and hear her voice emerge from Meryl Streep," he says. "And her performance as the old lady looking back is quite remarkable. Anyone who has relatives with dementia and who has witnessed that confusedness, but also that sort of struggle to pull oneself together - to say, I will not be crazy - I think what she does is extraordinarily moving."

Director Lloyd  says the actress did not use a dialect coach. But Streep pored over Thatcher recordings.

"The audiotapes were the most revelatory, because they showed this vast capacity . . . to speak sentence after sentence and never allow an interviewer to interrupt," Lloyd says. "The key to her will and ego, to the momentum of her thinking, was in the voice."