Britons should make a "heroic new year's resolution" to contact someone they have drifted apart from, the Archbishop of Canterbury has said.
Justin Welby called for the UK to "start healing some of the divisions that we've seen over recent years", in his new year message.
"It could be someone you've always wanted to connect with... [or] someone you really disagree with," he said.
"Pick one person. Pick up the phone. Send them a text."
The archbishop's message focused on heroism and hope - themes inspired by a recent visit to Dover lifeboat station.
It was broadcast on BBC One earlier and will be repeated on BBC Two at 16:30 GMT, as well as being available to watch on iPlayer.
Mr Welby met RNLI volunteers and was shown around a rescue boat as part of the programme.
"We rightly think of lifeboat crews as heroic, although they may be embarrassed to hear that. Yet every time we reach out and connect with someone, it is an act of heroism. Don't underestimate it," he said.
"Let's go for a heroic new year's resolution. Let's resolve to reconnect," Mr Welby added.
"To reach out to just one person we don't know, or from whom we have drifted apart... Meet them for a cup of tea. Make that connection. Let's begin cementing our unity one brick at a time."
'Decade of reconnection'
The archbishop's message is echoed in an open letter by leaders of prominent British organisations - including figures on both sides of the Brexit debate.
They say the 2020s should be a "decade of reconnection" and that people should resolve to "to start rebuilding connections between neighbours and fellow citizens".
They write that the UK "feels more fragmented than any of us would like", but add: "While our politics and media have become more polarised we, as people, have not. There is much that we share with each other."
The former heads of the Leave and Remain referendum campaigns, Matthew Elliott and Will Straw, are among the signatories, alongside Glastonbury Festival organiser Emily Eavis, Girlguiding chief Angela Salt, and CBI director Dame Carolyn Fairbairn.