The global wealthy will soon be able to send their children to a top English private school without having to leave home.
Harrow is setting up a virtual sixth form which will teach A-levels online to pupils anywhere in the world.
It will charge £15,000 per year and will initially focus on science and maths subjects, with education firm Pearson providing the technology.
The new Harrow School Online will begin teaching from September 2020.
Principal Heather Rhodes said the historic school was adapting to a "rapidly changing world".
This is the latest attempt to use online technology to sell UK education overseas - with the school's brand being used to attract pupils who want to be taught through the internet.
The online classes will only be available to pupils outside the UK - and so will not compete with its own bricks and mortar school in north-west London, where fees for boarders are almost £42,000 per year.
The school is expected to appeal to affluent families in Russia, China, Nigeria, the Gulf and Hong Kong, who want A-levels from a prestigious private school teaching in English.
Ms Rhodes said it might also appeal to families working abroad who want more flexibility than a conventional international school.
Harrow School Online will operate as a joint project with Pearson, which provides educational technology and also A-levels through its Edexcel exam board.
Sharon Hague of Pearson said the online platform had already been tested, and was being used by more than 75,000 pupils learning online in the United States.
The A-level subjects - chemistry, physics, maths, further maths and economics - will be taught through video-conferencing, with classes of up to 15 pupils per teacher.
The school expects to begin with a relatively small number of online pupils, but as the numbers grow, classes are likely to be scheduled around different time zones.
There will also be one-to-one teaching and extra-curricular projects, said Ms Rhodes, creating a "full-school experience".
Unlike the rest of Harrow, which only admits boys, the online school will teach both boys and girls - with entry depending on passing an admissions test.
Founded in the 16th Century, Harrow has taught many famous pupils, including Sir Winston Churchill and actor Benedict Cumberbatch.
The income will be shared between Pearson and Harrow, with the school saying money from online courses will be used to support bursaries for disadvantaged pupils.