The King said he has been “recovering” from having a “rather ancient birthday” as he began a series of engagements during a two-day trip to Dubai ahead of Cop28.
Charles met the president of Nigeria, Bola Ahmed Tinubu, on Thursday morning in the first of a number of bilateral discussions with world leaders.
The 30-minute meeting – ahead of an opening address to Cop28 on Friday – was the first with President Tinubu since Charles’s coronation.
The two men shook hands at a Dubai hotel and President Tinubu asked the King: “How are you?”
Charles, wearing a tanned suit, replied: “I’m all right very much… just about.
“Having had a rather ancient birthday recently, recovering from the shock of that.”
Charles celebrated his 75th birthday on November 14.
Later on Thursday, he will travel to meet students and graduates from across the Commonwealth to hear about green tech, sustainable innovations and the role of young people in delivering climate solutions.
The King has a number of engagements during his time in the Gulf state, including meeting global and Commonwealth indigenous leaders to discuss how traditional knowledge can protect against climate crises, and female climate leaders to discuss the risks posed to women by climate change.
On Thursday evening, he will join Sheikh Mohamed bin Zayed Al Nahyan, president of the United Arab Emirates, to formally launch the Cop28 Business and Philanthropy Climate Forum.
As part of the trip and his discussions with world leaders, Charles is also expected to promote peace in the region and worldwide.
His speech on Friday will mark the first time he has delivered the opening address at the conference as King, having previously opened Cop26 in Glasgow in 2021 and Cop21 in Paris in 2015.
Cop28 – or the Conference of Parties to the United Nations Framework Convention on Climate Change – begins at Expo City Dubai on Thursday and runs until December 12.
It will be attended by heads of state and government from across the globe, as well as delegates and climate bodies.
