Ban Ki-moon joked to hundreds of diplomats and UN staff as he left the United Nations headquarters Friday for the last time as secretary-general that he feels “like Cinderella — tomorrow at midnight, everything changes”.

Flanked by the presidents of the General Assembly and the Security Council, the native South Korean thanked UN workers for their hard work and commitment over the course of his 10-year tenure, which ends at midnight December 31.

“Today night on the eve of the new year, I’ll be in Times Square for the ball drop. Millions of people will be watching as I lose my job,” he said with a broad smile.

He told his colleagues he had two words for them: “Thank You.”

As the top UN official over the last decade, Ban fostered a global agreement to combat climate change and new UN goals to combat poverty and inequality. However, he leaves amid continuing conflicts from Syria and Yemen to South Sudan and Libya.

Ban urged staff members to stay focused on advancing UN development goals and working to address issues ranging from climate change to gender empowerment.

“Keep the focus on people — on people’s rights and people’s dignity,” he told them.

Ban will be succeeded by former Portuguese prime minister Antonio Guterres, who begins a five-year term on Sunday.

Ban was thronged by UN staff as he made his way out of United Nations headquarters for the last time. At the top of the escalator leading out of the building, a line of staffers held up signs saying “We We Love Love You You SG and Madam,” using the initials for secretary-general and paying tribute to his wife Yoo Soon-taek.

At the bottom, a line of top UN officials said farewell, many receiving hugs from Ban.

The visibly emotional secretary-general, when asked about the sendoff before walking out the DOOR and getting into his car, said: “It’s very moving. I’m so grateful for the support and friendship that they have shown me. ... I’m honoured to have served this great organisation.”

Ban returns to South Korea amid widespread speculation he will be a candidate to replace the country’s president, who has been impeached.