All adults aged 25 to 29 in England who have not yet had a Covid vaccine will be able to book their first dose from tomorrow.
The move brings the UK a step closer to meeting the target to offer all adults a vaccine by the end of July.
Vaccination can help stop the spread of coronavirus as well as protect people from getting sick.
This is key to helping the country continue to unlock, with Covid cases rising again linked to new variants.
In Scotland, people aged 30 and over are eligible for a vaccine. In Wales and Northern Ireland, everyone aged 18 and over are invited to book.
Two doses of vaccine are needed for strong protection against Covid, particularly the variant first found in India – also known as B.1.617.2 or Delta – that has been causing outbreaks around the UK.
It is now the dominant type in circulation and surge testing is happening to try to stop it spreading further.
Health and Social Care Secretary, Matt Hancock has said the end of all England’s coronavirus restrictions on 21 June could be delayed if concerns over the Delta variant intensify.
He told MPs: “It is too early to make decisions on step four, the road map has always been guided by the data and as before, we need four weeks between steps to see the latest data and a further week to give notice of our decision.
“So we’ll assess the data and announce the outcome a week today.”
NHS England chief executive, Sir Simon Stevens, said: “Getting the lifesaving Covid-19 jab is the most important thing you can do, with NHS staff vaccinating at over 1,600 sites including vaccine buses, places of worship, sport stadiums and other convenient locations.
“So, when you get that text, book your appointment and join the millions who are already protected.”
People aged 39 and under who are eligible and pregnant women will be offered the Pfizer or Moderna vaccine, in line with guidance.
In England, people can go online or call 119 to book.