Toffee, which launched in Britain last year, bills itself as the "world's first dating app for people who were privately educated".

Like Prime Minister Scott Morrison, Crowe attended Sydney Boys High School.

Kidman and Watts attended North Sydney Girls High while Mr Farquhar graduated from the selective James Ruse Agricultural High School.

Toffee founder and English private school alumni Lydia Davis said the app has a list of schools and users can add theirs if it's not on the list.

"We'll then double check the school, making sure it is independent/private," she told the Herald.

Users who sign up to Toffee are asked to indicate the school they attended from a long list that includes some unusual choices, including the exclusive Shore School's boat shed.

In other ways Toffee is similar to better-known apps like Tinder and Grindr. Users swipe to indicate their approval and are "matched" with potential partners who reciprocate.

Toffee's app costs $6.99 per month, cheaper than Tinder's paid tiers, though that service also has a free version.

"We set it up because we know people from similar backgrounds are more likely to stick together," Ms Davis said on the company's website.

There is evidence for Ms Davis' proposition. Assortive mating, in which people pair up with others who have similar levels of income and education, is on the rise long-term.

But the app will be less exclusive in Australia than in Britain, where about eight per cent of people are privately schooled.

"It's a niche dating app, with 34 per cent of Australians having been privately educated," Ms Davis said.

"We felt that Australia would be the best place for us to roll out to first though as we were inundated with requests for us to launch there."

Toffee is not the first dating app to have exclusion as a feature.

Grindr, the gay dating app, was sued in the United States last year over messages in users' biographies with messages like "No Asians".

It controversially allows paying users to filter by weight, height and ethnicity of their prospective partners.

Users of Hinge, another dating app, can set preferences for weight, height, ethnicity and religion.

Toffee does not use these filters.

"We have some fun functions on the app to get people talking but we've steered away from height, ethnicity filters. The app is all about trying to connect the users as quickly as possible, whether that's on the sliders, prompter questions, social calendar or perfect menu. We want to give some talking points," Ms Davis said.