Liam Neeson, Bono and Bob Geldof were part of a star-studded Irish presentation on Monday as the race hots up to host the 2023 Rugby World Cup, with France and South Africa also vying for the prize.
Hollywood actor Neeson and U2 frontman Bono voiced promotional films while Geldof read a poem by WB Yeats, also via video.
Irish Prime Minister Leo Varadkar said at the event in London that the bid also had the support of British counterpart Theresa May.
"She (May) has written to World Rugby supporting the bid and (saying) that the UK government is behind it and I am very grateful for her doing so," said Varadkar.
"I am here in person, the only head of government in person here," said Varadkar.
"We have also passed legislation through parliament with cross-party support.
"Also we have a fan base round the world through a huge Irish diaspora.
"One thing World Rugby want to do is break into the United States and we have proved through the match against the All Blacks in Chicago last year (which attracted 62,000 fans) we can bring that to the table."
South Africa had their vice-president Cyril Ramaphosa and the 1995 and 2007 World Cup-winning captains Francois Pienaar and John Smit in their delegation.
Ramaphosa evoked the name of Nelson Mandela, who, dressed in a Springbok shirt handed the trophy to Pienaar in 1995 when the nation last hosted the showpiece event in one of the most iconic sports images of all time.
He said a 2023 World Cup in South Africa would bring to fruition the dream of the late president.
"In 1995 it was an almost-white team," said Ramaphosa.
"In 2023 it will be a diverse rugby team and prove to the world what Nelson Mandela said, that rugby is a great unifier.
"It will be played out in reality that a country coming from a sad past, we will have achieved Nelson Mandela's dream of a true rainbow nation."
The French bid team produced a surprise, including the late New Zealand legend Jonah Lomu's children - seven-year-old Dhyreille and Brayley, eight - who had flown over from New Zealand with their mother Nadene.
"Dhyreille was born in Marseille when he (Jonah Lomu) came to play (played three games for Marseille in 2010)," said retired French international Sebastien Chabal, who had the brothers sitting on his knees.
"As he (Dhyreille) told us earlier, quite simply he is known at school as the 'Frenchie' and Jonah Lomu loved France."
French Rugby Federation president Bernard Laporte fronted up a video in which he held a team talk as he used to as France head coach.
He talked up the splendours of French cuisine and the attractions of the Parisian nightspot the Moulin Rouge helped by Claudine, a dancer dressed in a revealing red sparkling costume, with the slogan "Our World Cup will be your World Cup".
Laporte is under an investigation ordered by the French Sports Minister Laura Flessel for allegedly putting pressure on the Federation's appeals board to reduce punishments imposed on Top 14 side Montpellier, whose club owner Mohed Altrad is the biggest contributor to the 2023 campaign.
Flessel said nothing should be read into the non-appearance of President Emmanuel Macron, either in person or via video message.
The team had previously said he would make a contribution.
"I represent the state," said Flessel.
"The president couldn't come. We are very proud and the bid has the firm support of the government."
Rugby chiefs will make a final decision on who will host the 2023 event in London on November 15 after a technical report is released with a recommendation on October 31.
The winner needs 20 votes, with 39 available.
