Ricky Gervais, Michael Sheen and Lily Cole were among those who retweeted the Labour leader’s appeal for under-24s to ensure they had a vote in the poll on June 23.
With nearly 1.5m people between 18 and 24 not registered, the Labour In campaign launched a mass registration drive with Corbyn as its star attraction at a rally in Liverpool on Friday.
Labour insiders told HuffPost UK that one tweet by Corbyn had reached more than two million people in two hours, with 4 million impressions at one point.
The hashtag #InCrowd - a reference to the northern soul classic ‘I’m In With The In Crowd’ that accompanies Corbyn’s campaign - was trending on Twitter too.
Musicians Paloma Faith and Billy Bragg, comedians Eddie Izzard and Josie Long, former footballer Neville Southall and journalist Owen Jones referred the public to the voter registration page on the Government’s official website gov.uk.
The flurry of social media activity followed a speech by Mr Corbyn, where he told young people that it was their generation that would be most affected if the UK votes to leave the European Union and called on them to sign up to vote and to encourage their friends and family to do the same.
The event was designed to kick-start a massive push by the party to engage young people and make sure they register to vote before the June 7th deadline.
Chair of Labour In for Britain Alan Johnson MP told HuffPost UK: “Our campaign is all about reaching out to real people, and Jeremy’s rally today and the impact it’s had on social media shows exactly why he’s playing such a central role in convincing people that Britain is better off remaining in the EU.”
In his speech, Corbyn stressed that “the people who will be most affected if Britain leaves the EU will not be my generation, but your generation”.
He also pointed out that while Labour Party membership has doubled in the last year, its youth membership has more than trebled.
“We have more Labour Party members under 27 than UKIP or the Lib Dems have in total membership,” he said.
Corbyn, a past critic of a “bosses’ Europe”, said that an In vote was vital to protect workers’ rights and internationalism.
But he added: “That goes hand in hand with an agenda for progressive reform in Europe: to increase democratic accountability, tackle tax avoidance and climate change, and strengthen workers’ rights across the European Union.”
And in a dig at the Vote Leave camp’s ‘take control’ message, he said: “This is your chance to make it clear that a vote to remain is about taking control of your future."
Corbyn is set to appear in another Labour In event on Saturday, as the party ramps up its campaign with just six weeks to go to the referendum.