Isabella Soames, 16, a pupil at independent Brighton College in East Sussex, achieved one of the best sets of results in her school year and was planning to celebrate at Reading Festival.
The teenager is the daughter of Nicholas Soames, the Conservative MP for Mid Sussex and grandson of the wartime prime minister.
She was spotted by a scout from Storm while waiting for a bus on the King's Road in London and features on the model agency’s website in a section labelled “The Future”.
But the teenager plans to study ‘A’ levels in English, History, Latin and French and is unsure whether to pursue a career in modelling.
She said of being scouted by Storm: "I thought it was a bit weird, but then my mum said I should ring them up and I did.
"I haven't done any real jobs yet. I might get to do London Fashion Week in September but you tend to wait until you're older until you do jobs.
"I would definitely like to see how it goes but I don't know whether I would want to do modelling as a profession. It's a good thing to do if you can while you're at school."
She described her delight at receiving a string of top grades yesterday, saying: “I didn't know what to expect. I'm just really happy."
Isabella was among the best GCSE students in a record-breaking year at Brighton College, where 95.3% of grades were awarded at A* or A.