Almost half of teenagers coming to annual free Shakespeare performances for schools have never been inside a theatre before, research suggests.
More than 150,000 teenagers have been brought to Shakespeare's Globe in London over the past decade.
But a study of the audience shows that for many of these youngsters this will be their first sight of a live play.
The Social Mobility Commission heard warnings last week of "entrenched" inequalities in opportunities.
There have also been warnings of social "segregation" in schools - with youngsters living close together but having very different experiences.
"We hear from teachers that some London school students who come to the Globe, living only two or three miles away, have never seen the Thames before," said Georghia Ellinas, head of learning at Globe Education.
"While some families take going to the theatre for granted, there are a great many who never go and their children don't even see inside a theatre, let alone a production."
Despite most of these teenagers living in London, a survey of the audiences for school performances showed that 44% had never been to a theatre before.
Last week, Education Secretary Justine Greening highlighted that social mobility remained a "really hard long slog" - and how some youngsters were cut off from opportunities to widen their horizons.
The annual Playing Shakespeare project gives free tickets to state secondary school pupils for plays at the reconstructed Elizabethan theatre on Bankside - with 20,000 teenagers this year seeing The Taming of the Shrew.
The audience survey suggests the gulf in cultural experiences.
For some teenagers this encounter with Shakespeare was nothing unusual - with more than a quarter already having been to see other Shakespeare plays and just over half having been to a theatre before.
But for 44% this was their only experience of seeing a play on stage - and their teachers talked about how such trips could overturn expectations.
Danielle Bumford, head of drama at St Thomas the Apostle College in Peckham, south London, said it had "changed students' expectations from a rather negative view of Shakespeare".
Ms Ellinas, head of learning at the Globe, said this was a way of young people getting to see Shakespeare if "theatre-going is not part of a family's cultural history".
"Watching a performance with other people becomes a more visceral and vibrant experience. It is something every student should experience before they leave school," she said.
The free tickets, worth £2m, have been funded by Deutsche Bank, and Nicole Lovett from the bank said that as well supporting teenagers' academic studies, such trips benefited "personal development and future employability".
The Social Mobility Commission has investigated differences in access to cultural activities - seen as helping young people get into university or raise aspirations for jobs.
It found that trips to the theatre, galleries, the cinema or the zoo were all more likely for wealthier families - with the likelihood of such visits rising and falling in a way directly linked to family income.
The researchers were able to compare this data with cinema visits in the late 1960s.
Going to the cinema in the 1960s was not particularly linked to social background - and the very lowest earners were more likely to go to see films than the families of top professionals.
But the most recent figures show the cinema attendance is now closely related to income, with the wealthiest the most likely to see films.