The "Hug a Brit" campaign
calls on Europeans to post pictures of themselves embracing their UK friends
to social media, along with the hashtags #hugabrit and #pleasedontgouk.
Its organizers, a group of UK-based European nationals, hope to convince Britons to vote to remain in the EU in a national referendum on the issue in June.
Birgit Maass, a German journalist who has lived in the UK for 15 years, said she and fellow organizers thought up the campaign out of a desire to cast the debate in positive terms.
"The debate in the UK is very negative; it plays a lot on fear on both sides," she told CNN.
"We're stepping back and saying, it's not about fear, it's about something positive," she said.
"We need Britain to help us make things that aren't right within the EU better."
The campaign's website said
it sought to spread a message "from our hearts," rather than make an argument "about statistics, jobs or about the merits of EU rules on shower caps or cucumbers."
Britons will go to the polls June 23 to vote on whether to stay or leave the 28-member EU.
Europeans living in the UK enthusiastically took up the call to arms, using it as an opportunity to give their take on why a British exit, or so-called Brexit, from the EU would be to the detriment of both sides.
"London is the best place in the world because of the great mix of cultures," tweeted Roberta Cucuzza.
Christine Ullman tweeted a picture of herself with English pop star Jarvis Cocker, former frontman of the indie band Pulp.
"And yes, we're better together!" she wrote.
The campaign was also embraced by Europeans living on the continent, who signaled their support for Britain to stay.
Jean-Jacques Hublin, a French professor in Leipzig, Germany, tweeted a picture of himself with a British colleague, declaring himself against the Brexit.
Reserved Brits react
Britons themselves seemed largely flattered by the campaign, although some wondered how the prospect of random hugs would go over in a country noted for its emotional reserve.
"Please note that being hugged by a random stranger is the second most traumatic thing that can happen to a British person," Gordon Waugh tweeted.
"Ready and willing to cast off reserve and be hugged for my country in Europe!" tweeted Dominic Glover.
Others maintained a cultivated veneer of frostiness.
"First #hugabrit. Next we'll be forced to talk to Europeans on the Tube. The end is nigh," wrote one Twitter user.
Public opinion split on Brexit
British PM David Cameron called for the referendum
after wringing concessions from other European leaders that will grant the UK special status within the union if it opts to remain.
Cameron is campaigning to stay, but other high-ranking political figures, including members of his own Cabinet, are in favor of an exit.
Polling has shown consistently both campaigns neck and neck, with the latest YouGov poll
putting the remain camp at 39% and the leave vote at 38%, with 18% undecided and 5% saying they wouldn't vote.