Ironic Alanis Morisette
Samantha Cameron and Miriam Gonzalez Durantez were among 10 high profile women attending the event at Basildon Upper Academy in Essex, held as part of the national Inspiring Women campaign.
The campaign, run by the charity the Education and Employers Taskforce and backed by Bank of America Merrill Lynch, was launched to connect women from all backgrounds with girls from state schools.
The women took part in a "career speed dating" event with 100 girls to give them insights into different career options.
Aside from their political links, both Mrs Cameron and Ms Gonzalez Durantez are highly successful business women in their own right.
Mrs Cameron is creative consultant at the luxury stationery brand Smythson, while Ms Gonzalez Durantez is a partner at international law firm Dechert.
Others who passed on their career tips were space scientist Dr Margaret Aderin-Pocock, CNN's chief international correspondent Christiane Amanpour and writer and broadcaster Clare Balding.
Former culture secretary Dame Tessa Jowell talked about her experiences as a frontline politician, while former RAF officer Mandy Hickson told the girls about life as a fast jet pilot.
Speaking of her support for the Inspiring Women campaign, Mrs Cameron said: "Female role models are essential to giving young girls the motivation and confidence to follow their aspirations.
"Volunteering at a school for Inspiring the Future is a great way of ensuring dynamic, ambitious girls, like the ones I met today, are given every chance to think about their future and live up to their potential.''
Basildon Upper Academy, which is currently in special measures and has recently been inspected by Ofsted, is the first school in the UK to host an event as part of the Inspiring Women campaign.
Michael McCall, director of the school's sixth form, said: "Inspiring Women has given the school an opportunity to further support our female students' career advice and guidance.
"The school is constantly looking for ways to develop students' experience and knowledge."