LONDON — Michelle Obama's meeting with the Queen began with a handshake and ended in a hug.

U.S. President Barack Obama and his wife arrived Wednesday. After separate meetings on the eve of the G20 summit, the couple attended an evening reception for world leaders hosted by the Queen.

Michelle Obama clearly made an impression on the 82-year-old monarch -- so much that the smiling Queen briefly wrapped her arm around the president's wife in a rare public show of affection.

It was the first time Obama -- who is nearly a foot taller -- had met the Queen. She also wrapped her arm around the monarch's shoulder and back.

A Buckingham Palace spokesman who asked not to be identified because of palace policy said he could not remember the last time the Queen had displayed such affection with a visiting dignitary.

"It was a mutual and spontaneous display of affection," he said. "We don't issue instructions on not touching the Queen."

When the former Australian prime minister Paul Keating put his arm around the Queen in 1992, the tabloids dubbed him the "Lizard of Oz." When his successor, John Howard, was accused of doing the same, a spokesman insisted: "We firmly deny that there was any contact whatsoever." In 2007, U.S. President George W. Bush gave the Queen a sly wink during a visit she paid to the United States.

Canada had its own touching-the-Queen kerfuffle some 25 years ago when British tabloids reported Ontario Transportation Minister James Snow touched the Queen's back and elbow during a royal visit.

One tabloid, the racy News of The World, ran a front-page story with the headline "Hands Off Our Queen." Snow denied touching the Queen's back and said if he did touch her elbow, it was by accident.

Royal protocol apparently states those who meet the Queen should not touch her except when she offers her hand.

As for the Obama visit, the Daily Mail said the "two women clearly took to each other."

Wednesday's reception was followed by a dinner at Prime Minister Gordon Brown's Downing Street home, where the leaders' spouses were joined by notable British women, including "Harry Potter" author J.K. Rowling and Olympic gold medal-winning runner Kelly Holmes.

"Michelle walks in and she is as she seems," Holmes told reporters Thursday. "So warm, engaging, a beautiful, beautiful lady -- and I quickly got my photo in the middle of her and Sarah Brown," the prime minister's wife.

Obama also seemed to win over the often feral British press.

The last time a president's wife was such a hit in Britain was last year when French President Nicolas Sarkozy visited along with his wife, the former fashion model and songwriter Carla Bruni.

But on Thursday, London's Times newspaper had moved on, writing "Carla who?"

The BBC described Michelle Obama as her husband's co-star rather than supporting act, appropriate for a Harvard-educated lawyer.

Obama visited an all-girls school in north London on Thursday afternoon. She told the 240 girls about growing up on Chicago's south side, and urged them to think of education as "cool."

"I never cut class. I liked being smart. I liked getting A's," she said. "You have everything you need. Everything you need to succeed you already have right here."

At the end of her visit, Obama doled out hugs to the students, and was swarmed by them, to the extent that some Secret Service agents stepped nervously forward.

Earlier Thursday, Obama attended a performance at the Royal Opera House with the other leaders' spouses and guests. The program included music by Handel and a dance performance by Ballet Black, a troupe set up to give performing opportunities to black and Asian classical dancers.

Wearing a bright teal blue dress by Jason Wu -- who designed her inauguration gown -- and a sweater by Junya Watanabe, Obama posed for photographs with Sarah Brown, Therese Rein, wife of Australian Prime Minister Kevin Rudd, Japanese Prime Minister Taro Aso's wife Chikako Aso, and Laureen Harper, wife of Canadian Prime Minister Stephen Harper, on the stage of the opera house.