People who live alone in England and Northern Ireland will be able to form a support bubble with another household from Saturday, in a further easing of coronavirus lockdown rules.
Adults who live alone will be allowed to visit someone else's home and are even allowed to stay overnight.
In England, the rule also applies to single parents with children under 18.
It comes as charities warned about isolation, with the latest changes aimed at helping those who are lonely.
The new measures open up the possibility for grandparents who live alone to visit and hug their grandchildren for the first time since lockdown began.
Couples who live apart will also be able to be close to each other again.
It comes as the UK death toll rose by a further 181.
According to the latest figures, released on Saturday, 41,662 people who tested positive for coronavirus - across all settings - have now died.
The latest relaxation of the lockdown rules in England was announced by Prime Minister Boris Johnson earlier this week.
A person's bubble can be with one other household of any size and close physical contact is allowed, meaning people in the bubble do not have to stay 2m apart.
But Mr Johnson said support bubbles must be exclusive, meaning someone can only form a bubble with one other household and they cannot swap.
If anyone in the bubble develops symptoms of coronavirus, then everyone in the bubble must self-isolate.
Northern Ireland has introduced a similar scheme, allowing people who live alone indoor visits with one other household.
Neither the bubble measures in England or NI apply to people who are shielding.
In Scotland, the government is considering the idea, while the Welsh government is reviewing the next steps out of lockdown.
Among those who are looking forward to Saturday's changes are 70-year-old Sarah Griffiths Hughes, from Dorset, who said she is looking forward to hugging her daughter for the first time in months.
"It's the loneliness," she said. "I don't think people realise how lonely and frightened we all are."
Keith Grinsted, from Sudbury in Suffolk, said he was "welling up just thinking about" hugging his daughters, who live with his ex-partner.
But as he has type-2 diabetes, making him vulnerable to coronavirus, and he still has concerns about his safety.
He said: "Even now it is still quite worrying, for example, because one of my daughters works for a fashion retailer and they are opening on Monday and she has her first shift on Thursday next week, now we are discussing, okay we can have a hug on Saturday but once she starts working does that still mean it is safe to hug?"
Also from Saturday in NI, the maximum number of people who can gather outside together has also been increased to 10. In England, that number is six, while it is eight in Scotland and unlimited in Wales.
The latest papers published by the UK government's Scientific Advisory Group for Emergencies (Sage), revealed that last month some experts urged "strong caution" that allowing bubbles could cause "significant unwanted effects" - especially if it was accompanied by lifting other restrictions.
It also warned there was "significant potential risk" if larger households are allowed to bubble together - although the government's new rules only apply to single-person or single-parent households.
It comes ahead of the next stage of easing lockdown in England, as non-essential shops prepare to reopen on Monday.
Shops in NI began opening on Friday, with customers encountering queuing systems, screens at tills and shop workers wearing masks.
No dates have been set for the reopening of non-essential shops in Scotland and Wales.
It comes after figures showed the UK economy shrank by 20.4% in April - the largest monthly contraction on record.
Meanwhile, there are growing calls for the government to drop the 2m social distancing rule in England, with Tory MPs saying it is essential for the economy.
The government has said it is constantly reviewing its coronavirus lockdown guidance.
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