Irish president Michael D Higgins has hailed his "memorable" historic state visit to the UK as "so positive, so uplifting and so hopeful".
He took to the Royal Albert Hall stage at a concert in his honour to uproarious applause and said: "On a night like this it is great to be Irish." He added it was "even better" to share it with "our friends in Britain".
On the final night of his historic state visit, the London venue was the setting for an evening of music, song, dance and literature featuring artists from the two nations.
President Higgins was joined in the Royal Box by his wife Sabina and Prince and Princess Michael of Kent.
Northern Ireland's Deputy First Minister Martin McGuinness was seated next to the Royal Box, accompanied by First Minister Peter Robinson, Northern Ireland Secretary Theresa Villiers and former prime minister John Major.
President Higgins took to the stage shortly before the final notes of the concert Ceiliuradh (Celebration) rang out.
"In this magnificent venue and on this...historical occasion, I want to extend my thanks to a number of people who have made this evening's celebration, and indeed the past few days, extraordinary and memorable days, so positive, so uplifting and so hopeful," he said.
The president expressed his and his wife's "deep appreciation" to their hosts, the Queen and the Duke of Edinburgh, thanking them for their "gracious and generous welcome and the warm hospitality".
Mr Higgins joked that he hoped Prince and Princess Michael were "sufficiently entertained" and would "transmit positive review" to the Queen about the concert.
President Higgins described the cultures of the two nations as "deeply interwoven".
Performing on the night, hosted by Dermot O'Leary, were stars including Glen Hansard, Imelda May, Paul Brady, and special guest Elvis Costello.
President Higgins thanked the Irish living across the water for "the contribution you've made to the development of Britain, and for your part in the consolidation of an enduring friendship between our two countries".
He added: "A friendship that will grow and deepen and become richer as a result...of this memorable week.
"I want to tell you that you remain and will always be, all of you, a cherished member of the Irish family."
He thanked everyone for travelling to be at the historic concert, and said: "On a night like this it is great to be Irish.
"And it is even better to share with our neighbours... our friends in Britain."
Taoiseach Enda Kenny was also at the event.
The cultural evening began with the singing of the two national anthems, after President Higgins took his place in the Royal Box - a moment that prompted a standing ovation, much applause and cheering.
Host O'Leary got a lively reaction from the crowd when he referred to Ireland's recent Six Nations win.
The X Factor presenter, who was born in Britain but whose parents hail from Ireland, said: "I was reliably informed I was made in Ireland."
In a reflection, Irish journalist Olivia O'Leary joked: "It's now official. We are allowed to like the British."
Ms O'Leary listed the things Irish people like about Britain, including Aintree, Cheltenham, Manchester United and the BBC.
About the BBC, she said: "And we watched it for years without paying a licence free and we're utterly unrepentant about that."
She joked that it could be viewed as "a down-payment on the debts of empire".
Of the relationship between the two nations, she said: "We'll always be different. We'll always be proudly separate."
But, she added, both nations would "always be a little part" of each other.
One of the more raucous moments of the night was when the hundreds of people in the venue took part in a singsong for The Auld Triangle.
After President Higgins' speech, the evening finished with a reading of a Seamus Heaney poem and a rendition of The Parting Glass.