Bill Clinton said he was "very grateful" as he attended the unveiling of a portrait of him by Belfast artist Colin Davidson in New York

Davidson, who has painted everyone from Ed Sheeran to Queen Elizabeth, produced the artwork to acknowledge Clinton’s "vital role" in the Northern Ireland peace process by brokering the 1998 Good Friday Agreement.

Speaking at the unveiling ceremony at Clinton’s Foundation’s offices, the 72-year-old former president said the portrait, which he sat for last year, captured a part of him that few have seen.

"I'm no longer young. And I'm not smiling through a crowd. I'm thinking about the challenges we face, and hoping for tomorrow" - former US president Bill Clinton | https://t.co/uQEdGH9otX pic.twitter.com/IekKAcmluD

— RTÉ News (@rtenews) June 18, 2019

He told RTE, "This actually captures a part of my personality I often try to keep hidden because I try always to be upbeat, I always try to be positive and I always to think that the best is around the corner.

"I am very grateful because the painting shows me in a way I would not be prepared to show myself, in my 'I don't know, but I sure hope so' mood.”

Clinton also spoke about the effect of Brexit on Northern Ireland, saying he had "always been worried" about Britain leaving the EU without considering potential damage to the North.

Read more: Bill Clinton concerned about Brexit’s impact on Northern Ireland

"Those who want a hard Brexit are portraying it as the liberation of the U.K., but if you look at the population trends and the wealth and productivity trends, they could be consigning one of the greatest nations in human history to a smaller role," he said.

"I don't like living in an age of resentment and division, I like living in an age of possibility and hope."

Davidson said his portrait was an attempt to show Clinton's empathy and compassion for everyone on the island of Island, describing it as an "Irish painting" rather than an American-inspired work.

Clinton’s day of Irish events on Monday ended with him accepting an award from the Irish Repertory Theatre at Lincoln Center on behalf of his work on the peace process.

Read more: Fleetwood Mac take Dublin by storm, perform "Dirty Old Town"

Former President Bill Clinton and artist Colin Davidson at the unveiling in New York on Monday.