Michelle Obama skyped girls at an east London secondary school today as part of the International Day of the Girl.
The US First Lady gave an empowering speech to pupils across the world on the benefits of education.
Mulberry School for Girls in Tower Hamlets was among the schools across the globe chosen to be included in the Skype conversation.
Mrs Obama, speaking from Washington DC, said: "Education is a very personal thing for me, as I tell girls whenever I meet them.
"I wouldn't be here sitting here, not just in this chair, but in the life that I have if it weren't for my education."
She said the world cannot afford not to educate girls and it was her “mission” to ensure girls everywhere have the same opportunities to learn and thrive.
Mrs Obama, who launched the Let Girls Learn initiative aiming to help more than 62 million girls worldwide who are not in school, visited Mulberry School last year.
She told those gathered and others watching online: "Making sure that girls around the world who are just as bright, just as able as me, have the same opportunities to take their education seriously, to have access, has become a mission that I take very seriously.
"This is something that means a great deal. We can't afford not to educate girls and give women the power and the access that they need so we're going to keep working hard."
Mrs Obama took questions from schoolgirls in locations including Cambodia and Tanzania. She laughed when one of the pupils in Tanzania addressed her as "First Lady of the World", replying: "I like that promotion, thank you."
The First Lady said she wanted to push the message that young girls in countries with free access to education should not take this opportunity for granted.
She said: "I want kids here in the United States and in other parts of the world to understand that there are girls that are willing to give their life, they are literally dying trying to get the education that many of us take for granted.
"And if we really want to honour these girls like Malala (Yousafzai) and like the girls in Nigeria (abducted by Boko Haram) and girls in Tanzania who would give anything to get an education, then the very first thing we have to do is take our education seriously and not take it for granted - to be that voice."
She added: "So this is one of the reasons why we can't afford to ignore this issue."
Mrs Obama said the advice she would give her 16-year-old self, and a message she gives her daughters "every day" is: "Do not be afraid to fail."
The First Lady said her work on the issue of education will continue long after she leaves the White House with President Obama in January, when a new President is inaugurated.
