Social gatherings of more than six people will be illegal in England from Monday - with some exemptions - amid a steep rise in coronavirus cases.
A law change will ban larger groups meeting anywhere socially indoors or outdoors, the government said.
But it will not apply to schools, workplaces or Covid-secure weddings, funerals and organised team sports.
It will be enforced through a £100 fine if people fail to comply, doubling on each offence up to a maximum of £3,200.
Several exemptions apply to the new rules - which come into force on 14 September - with households and support bubbles bigger than six people unaffected.
Prime Minister Boris Johnson is expected to give further details at a Downing Street news conference later on Wednesday.