The snapshot of the Danish prime minister's 'selfie' caused a stir around the world; with the First lady looking distinctly unimpressed in the background as her husband and his counterparts grinned for the camera.
But it is a misleading image, according to Roberto Schmidt, the AFP photographer responsible for the picture.
"Anyway, suddenly this woman pulled out her mobile phone and took a photo of herself smiling with Cameron and the US president," Roberto wrote in a blog for AFP.
"I captured the scene reflexively. All around the stadium, South Africans were dancing, singing and laughing to honour their departed leader. It was more like a carnival atmosphere, not at all morbid.
"The ceremony had already gone on for two hours and would last another two. The atmosphere was totally relaxed – I didn't see anything shocking in my viewfinder, president of the US or not. We are in Africa.
"I later read on social media that Michelle Obama seemed to be rather peeved on seeing the Danish prime minister take the picture. But photos can lie. In reality, just a few seconds earlier the first lady was herself joking with those around her, Cameron and Schmidt included. Her stern look was captured by chance.
"I took these photos totally spontaneously, without thinking about what impact they might have. At the time, I thought the world leaders were simply acting like human beings, like me and you. I doubt anyone could have remained totally stony faced for the duration of the ceremony, while tens of thousands of people were celebrating in the stadium.
"For me, the behaviour of these leaders in snapping a selfie seems perfectly natural."