Stepping off the aircraft in Moscow - the first stop of President Xi Jinping's maiden foreign trip since assuming office - Peng's glamorous appearance and obvious affection for her portly husband caused Chinese microbloggers to swoon.
"So beautiful, Peng Liyuan, so beautiful! How composed, how magnanimous," wrote one user on China's popular Twitter-like service Sina Weibo.
"Who could not love such a lady as this and be insanely happy with her?" wrote another.
Taobao, an online shopping site similar to eBay and Amazon, quickly began offering for sale coats in the same style of Peng's, advertising it as "the same style as the first lady's".
Others wondered what brand her bag and shoes were.
"Her shoes are really classic, and who designed her bag?" wrote a third Weibo user.
Peng is best known in China as a singer, and for many years was arguably better known and certainly more popular than her husband.
People who have met her and know her say that Peng is vivacious and fun to be around, though she was ordered to take a back seat after Xi became vice president in 2008 as he was being groomed for state power.
But she is expected to be given high-profile events of her own to attend on Xi's sweep through Russia, Tanzania, South Africa and the Republic of Congo on a week-long trip, as the government tries to soften the image of China abroad.
Peng has won praise for her advocacy for pet causes, most notably for children living with HIV/AIDS, and may visit charities related to this while abroad.
Unlike the baby-kissing politicians of the West, China's Communist Party works hard to keep its top leaders from appearing too human - to the point that for many, even their official birthdates and the names of their children are regarded as a state secret.
Xi and Peng are different. Their romance has been the subject of dozens of glowing reports and pictorials in state media.
"When he comes home, I've never thought of it as though there's some leader in the house. In my eyes, he's just my husband," Peng gushed in an interview with a state-run magazine in 2007, describing Xi as frugal, hardworking and down-to-earth.
Peng is Xi's second wife, and the two have a daughter studying at Harvard under an assumed name. Xi divorced his first wife, the daughter of a diplomat.
Chinese first wives have traditionally kept a low profile over the past few decades, 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.