Britain's Queen Elizabeth asked a fishmonger if he had brought any fish with him during a reception at Buckingham Palace in London.
The Queen made the light-hearted remarks at the reception attended by 300 members of the Irish community.
Cork fishmonger Pat O'Connell recounted how he met the royal at the English Market in Cork during her visit to Ireland in 2011.
Mr O'Connell made quite an impression during that visit, when he shared a joke with the Queen and the Duke of Edinburgh about an unattractive monkfish, which he said was nicknamed "the mother-in-law fish".
And at the Palace this evening, Mr O'Connell said he was "surprised" to be so swiftly recognised by the Queen, who he said greeted him by saying: "You're here, have you bought any fish with you?"
Mr O'Connell said: "We had great fun in Cork when she visited.
"I told the Queen when she last came to see me was the week of my 30th wedding anniversary and I said that the last time I was this well-dressed was 33 years ago."
"She laughed and then she asked me if I brought her any fish."
Mr O'Connell also sent the Queen a copy of his autobiography, 'The Fishmonger' and signed a photo of them in Cork. "Apparently it's hanging somewhere around Buckingham Palace," he added.
"I'm very surprised to be here. I sell fish in Cork. I'm one of 44 traders and any one of them could have been here tonight. I was just very lucky I hit it off with the Queen when she arrived and am here representing Cork and the English market."
The Queen and the Duke chatted with Irish guests from the world of sport, business, politics, the arts, and community work, who have all made a positive contribution to Britain.
Guests included One Direction singer Niall Horan, X-Factor judge Louis Walsh, fashion designer Orla Kiely, racehorse trainer Jonjo O'Neill and former Formula One racing boss Eddie Jordan.
Horan described being at the Palace as "mind-blowing".
"It's an absolute honour to be here with two great countries coming together. I couldn't believe it when I got the invitation. To have met Her Majesty again was a great experience."
Horan, who had just come from rehearsing with his bandmates, said that they were pleased for him: "They were really happy when I told them. They know it's an Irish thing so they're not being left out."
"I might ask her if she wants to come to a show", he joked.
The Princess Royal, her husband Vice Admiral Sir Timothy Laurence, the Duke and Duchess of Gloucester, and the Duke of Kent were also at the Palace.
The Irish ambassador to Britain, Dan Mullhall, and Teresa Villiers MP, the secretary of state for Northern Ireland, also attended.
The reception took place before the first official state visit by an Irish President to Britain next month.
President Michael D Higgins will be in the UK in April following the Queen's visit to the country three years ago, when she became the first British monarch to visit the Republic.
Reality TV judge Walsh said the Queen told him she would love to come back and visit the country.
"We talked about her visit to Ireland, she said she had a wonderful time and that she'd love to come back again.
"She said she thought she picked the perfect moment to come while Mary McAleese was still president.
"She is an amazing woman and she proved that on her visit. Everybody loves her.
"I didn't ask if she watches The X Factor but I think she might be watching Strictly Come Dancing."
A spokesman for Buckingham Palace commented on President Higgins' forthcoming visit, calling it "exceptional", adding: "All states visits are important and this is one is both exceptional and historical.
"Because of the phenomenal success of the Queen's visit to Ireland in 2011, where she was made to feel very welcome, there is a sense that visit was a really important moment in the bilateral relationship."
"From the Queen down, everyone is wholeheartedly invested in the visit by the President and would like to return the hospitality. This evening's event kicks off that process."
Mr Mulhall said there was "never a better time to be Irish in the UK".
"It is a wonderful occasion for the Irish community in Britain, the biggest Irish community anywhere in the world outside of Ireland," he said.
"They have made a huge contribution to Britain over the years, a huge contribution. Many of the people here tonight have been here for 40, 50 or even 60 years but they still have a proud Irish identity."
Ms Villiers said: "I think that the bilateral relationship is better than it has been at any time in the last 800 years. The President's visit is a wonderful opportunity for the Irish to celebrate the huge contribution they've made to life in Britain. This is a great curtain raiser to that."
Ms Villiers added: "Of course there are still many problems to be resolved in Northern Ireland but it's wonderful to be here to celebrate the successes."
The Queen was wearing a diamond broach shaped in the form of a shamrock and an evening suit designed by her senior dresser Angela Kelly.
Father Ted creator Graham Linehan was also in attendance and had a handwritten letter from his eight-year-old daughter to hand to the monarch.
Mr Linehan said: "We have never had anything other than an extraordinary welcome here. I don't think the Irish contribution needs to be validated, as such, but if it is going to be validated then what better place to do so than Buckingham Palace."
"I will certainly have something to tell my daughter," he added.
The evening was kicked off by traditional Irish music played by Comhaltas, an international Irish organisation who are tasked with the promotion and teaching of Irish music all over the world.
Alongside stars from the world of showbiz, community workers were also recognised for their efforts.
Headteacher Jerry Collins was invited for transforming under-performing London school, Pimlico Academy. In two and a half years, Mr Collins achieved outstanding status with the school and was hailed by Ofsted for his "outstanding vision and leadership"
Mr Collins is now the principal of ARK John Keats Academy which opened last September.
He said: "It's fantastic to see so many Irish in Buckingham Palace. There was a thawing of relations between our two countries and seeing the President coming over here is fantastic because years ago a lot of Irish may have been reluctant to come to the Palace. Now we're very welcomed. The Irish community have contributed to the development of British life in so many ways, from education to business."
A spokesman from Buckingham Palace added: "It was a really fun evening - great company and extremely relaxed. Her Majesty seemed to enjoy the craic."