Meryl Streep, best actress winner for her role in The Iron Lady, holds out her Oscar statuette backstage at the 84th Academy Awards in Hollywood, California. Mike Blake / Reuters

Meryl Streep continues her career-long award streak with an Oscar for her portrayal of Margaret Thatcher. Ronald Grover of Reuters reports from Los Angeles.

Meryl Streep, who holds the record with 17 for the most Academy Award nominations by any actor, won the Oscar for best lead actress on Sunday (Monday, Beijing time) for her portrayal of former British Prime Minister Margaret Thatcher in The Iron Lady.

It was Streep's third Academy Award, but her first since winning the Oscar for Sophie's Choice in 1982. She was also honored for the 1979 film Kramer vs. Kramer, and had long been considered overdue for another Academy Award.

Accepting her award, Streep sounded less like a winning actress than a star who had just received a lifetime achievement award.

"I really understand that I'll never be up here again," she said, in an emotional speech in which she congratulated Roy Helland, her hair stylist for 37 years and who shared this year's Oscar for makeup with Mark Coulier for The Iron Lady.

"I look out there, and I see my life before my eyes," said Streep, addressing an audience packed with the biggest names in the movie industry. "When they called my name, I had the feeling I could hear half of America going, 'Oh, no. Come on'."

The 62-year-old is widely regarded as the best living movie actress, and most critics say she turned in her best performance ever as Thatcher.

She won her first Oscar at age 30 for Kramer vs. Kramer, her fourth feature, according to the movie website IMDB. "I was a kid when I received the first nomination," she said, in comments to reporters backstage.

"Two of the nominees (tonight) weren't even conceived."

In The Iron Lady, she plays the feisty British leader both as a woman at the height of her power in the 1980s and as an old and lonely woman suffering from dementia in the present day.

Streep first appeared onscreen in 1977 in Julia after having honed her craft at the Yale School of Drama and onstage.

She quickly became known for the depth and breadth of her characterizations, and for her gift with accents, such as the Polish Holocaust survivor she played in Sophie's Choice.

Dozens of other movies followed, ranging from romantic fare like Out of Africa and The Bridges of Madison County to biographical movies, such as Silkwood, and dramas like Doubt and the HBO television series Angels in America, for which Streep won an Emmy.

She was presented the Oscar by Colin Firth, who won a statue for best actor last year for The King's Speech and who starred with Streep in the 2008 film Mamma Mia!.

"Mamma Mia," joked Colin Firth. "We were in Greece. I was gay. I probably fathered her daughter."

In 2006, Streep changed direction to comedy, playing a ferocious fashion boss in The Devil Wears Prada and then camping it up in her first musical Mamma Mia!.

She followed up with a dead-on impersonation of TV cook Julia Child in Julie & Julia and showed her flair for romantic comedy with It's Complicated opposite Alec Baldwin.

"You are unreasonably good," Firth said to Streep in his introduction before announcing the name of the winner.

"Whatever role you play you raise the bar, making it a little more difficult for the rest of us."