Dentists and opticians will now offer blood pressure tests in a bid to slash the risk of Brits suffering a heart attack and stroke.
Under the scheme, more than 60 practices in England will offer the checks as part of routine appointments.
Officials estimate it could see 100,000 patients tested over the next 12 months, who may otherwise have gone unchecked.
Dubbed a 'silent killer', more than 14 million adults in the UK have the potentially deadly condition — known medically as hypertension.
But as many as five million of these are thought to be undiagnosed, according to the British Heart Foundation.
Often high blood pressure has no symptoms until it is too late but is also linked to a higher risk of kidney disease and even vascular dementia.
The checks will be carried out by trained staff including dental nurses, optical assistants and technicians, at no extra charge.
The rollout was announced at the European Society of Cardiology Annual Conference in London.
Helen Williams, NHS national clinical director for cardiovascular disease prevention, said: 'These convenient checks at dentists and optometrists will enable thousands of people to monitor their blood pressure and could potentially be life-saving.
'Many otherwise healthy people over 40 only visit their GP when they're feeling unwell, but offering these vital checks as part of routine dentist or eye test appointments means we can identify and support more people at risk.
'High blood pressure is a significant factor in many cardiovascular diseases but as it usually has no symptoms, many people don't know they have it, so I would urge anyone offered a check to come forward.'
Sonya Babu-Narayan, associate medical director at the British Heart Foundation and a consultant cardiologist, added: 'Concerningly, up to 4.2 million people in England may be living with high blood pressure and don't know it.
'High blood pressure is usually easy to treat, and that's why it is vital to get yourself checked.
'Blood pressure tests are very simple and easy, so if your dentist or optician can provide it, do take up the opportunity to get yourself tested — it could save your life.
Health officials are concerned about a rise in heart deaths among men since the pandemic, with men less likely than women to take up the offer of an assessment.
Dental chiefs, however, warned proper funding would be needed for the scheme to work effectively.
British Dental Association chair Eddie Crouch said: 'Shrewd investment here could prevent disease and save our NHS a fortune.
'Dentists are ready to play their part, but any gains will remain purely theoretical without the funding and reform required to save this service.'
Latest NHS figures also show roughly 26million adults — roughly 60 per cent of the population — haven't had a check-up in the last two years.
This is one of the lowest proportions since modern records start in 2006.
NHS dentistry has been in crisis for years, with leaders claiming the sector has been chronically underfunded, making it financially unviable to carry out treatments.
Exacerbating the problem is that, as more dentists leave the NHS, those that remain become swamped by more and more patients.
Brits have also told how they have been sat on waiting lists for months and travel abroad to see a dentist after finding it impossible to get an NHS appointment, slamming the system as 'Victorian'.
Others have been forced to pull out their own teeth with pliers or travel abroad for treatment.
It comes as the NHS last week also announced it would roll out health MoTs to offices and factories from next month as part of a major drive to catch heart disease and diabetes early.
Checks including blood pressure, BMI and blood tests for cholesterol and blood sugars will be offered to middle-aged workers, from bus drivers to care workers.
Health chiefs hope by targeting 130,000 people in their workplaces, they will reach those at highest risk.
Under the launch of Pharmacy First earlier this year, nine in ten chemists across England also now offer the checks.
Between January and June, 1.4 million walk-in tests were delivered.