But the glamorous and popular wife of Chinese President Xi Jinping stepped out of the spotlight for two days in California while her husband held unprecedented informal talks with U.S. President Barack Obama at a lush retreat in the desert on the last leg of a four-country trip.
Peng, a singer who many Chinese say was far more famous than Xi before he became a top leader, has decisively broken the mold of Chinese first wives who have kept an intentionally low profile since the 1970s.
Many in China expected to see more of her in California and hoped that she would have a chance to interact with U.S. First Lady Michelle Obama, potentially adding a fresh dimension to the nascent relationship between their presidential husbands.
But Mrs. Obama's decision to stay in Washington with her daughters rather than meet the Chinese first couple sidelined Peng to some extent.
U.S. officials said it had been made clear to the Chinese side early on that a scheduling conflict would prevent Mrs. Obama from the summit at the Sunnylands estate near Palm Springs.
But the U.S. first lady did make a gesture.
"Mrs. Obama wrote a letter to Madame Peng welcoming her to the United States. The First Lady said she regretted missing her this weekend but hopes to have the chance to visit China and meet Madame Peng sometime soon," a White House official said.
Still, Michelle Obama's absence set the Chinese blogosphere and some Chinese media outlets alight with speculation, anger, pride and more than a few jokes.
It was an "arrogant show of fear of inferiority" which caused Michelle Obama not to meet Peng, and an insult to the Chinese people, an opinion piece carried by the semi-official China News Service said. The article appeared to have later been removed from the service's website but it was widely circulated on China's Twitter-like Sina Weibo microblog.
'DISRESPECT AND RUDENESS'
"Even if Xi's wife doesn't care, many Chinese believe this is a show of disrespect and rudeness towards the Chinese leader," it said.
Michelle Obama has had cordial interactions with other foreign leaders' wives who have visited the White House as well as with those she has met abroad. But lacking any major diplomatic role in the administration, she has shown few signs of forging close personal bonds with her foreign counterparts.
On Weibo, several commentators took their own stabs as to why Michelle avoided California.
"She was afraid of Mama Peng's charm. How shameful that the aura of the First Lady of the world's superpower can't beat that of the First Lady of developing China," wrote a user with the handle Chiki_Wang.
Another wrote: "Michelle decided to hide before being humbled. She was afraid that after dinner the two couples would sing karaoke and so she said she needed to be with her daughters - one of the most common excuses, even in China."
Peng stepped into the limelight in her new role as first lady in March, the same month that Xi became president, when she accompanied him to Russia and Africa. She became an instant internet sensation back home.
Images of her wearing a fashionable, made-in-China wardrobe have been popular back home - a parallel she shares with Michelle Obama, who Vogue magazine said in its April cover story had "inspired a modern definition of effortless American chic."
Chinese first wives have occasionally appeared in photographs when traveling abroad with their husbands. Most have appeared frumpy and awkward, though, and none of Peng's predecessors stretching back to the founding of the People's Republic of China in 1949 could be described as glamorous.
All have kept a low profile because of the experience of Jiang Qing, the widow of the founder of Communist China, Mao Zedong. Jiang was the leader of the "Gang of Four" that wielded supreme power during the 1966-76 Cultural Revolution. She was given a suspended death sentence in 1981 for the deaths of tens of thousands during that period of chaos.
By contrast, Peng's easy, casual and fun demeanor were on full display once again on the earlier leg of Xi's trip, which took in Trinidad, Costa Rica and Mexico. She has also been trying out her English, which sources with ties to the leadership told Reuters she has been learning.
In California, Palm Springs' local newspaper, the Desert Sun, snapped photos of her visiting the Palm Springs Art Museum on Friday afternoon. Almost no other media were present.
And Peng joined Obama and Xi for tea on Saturday before the Chinese first couple departed, U.S. national security adviser Thomas Donilon said. It lasted about a half hour.
(Additional reporting by Matt Spetalnick in RANCHO MIRAGE and Ben Blanchard in BEIJING; Editing by Alistair Bell and Eric Walsh)