The President-elect took to Twitter to say the process of choosing his White House staff has been 'very organised'
Donald Trump promised restaurant diners: "I'll get your taxes down, don't worry about it", after slipping away from reporters to go for a family dinner in New York.
The President-elect's team told journalists he had no further engagements - an hour before his motorcade left Trump Tower.
His whereabouts were confirmed when a diner at the 21 Club tweeted a picture of Mr Trump arriving with his family and the secret service.
Surprised diners greeted Mr Trump with applause, handshakes and calls of "thank you", before he took his seat at a small round table with his wife Melania, daughters Ivanka and Tiffany and daughter-in-law Lara Yunaska.
Video by journalist Hallie Jackson, who had a prior reservation, showed Mr Trump responding to the applause with: "I'll get your taxes down, don't worry about it."
The plush Manhattan restaurant, a former speakeasy during America's prohibition era, has hosted every US president since Franklin Roosevelt - except George W Bush.
Also present at the dinner were son-in-law Jared Kushner and daughter-in-law Vanessa, who is married to Donald Trump Jr.
The unexpected appointment frustrated reporters used to the White House allowing a journalist to be near the president at all times to relay his first comments in the event of breaking news.
Mr Trump has an uneasy relationship with news crews.
During his presidential campaign he condemned the media's behaviour, saying "there has never been dishonesty like it".
Meanwhile, the President-elect has indicated the process of choosing his White House staff has been 'very organised'.
Some media reports have suggested the transition team is in 'disarray'.
Ben Carson - who has been noted as a favourite for a cabinet position - told the Washington Post he is unlikely to join the administration.
Two key appointments have been made so far - Republican National Committee chairman Reince Priebus as Chief of Staff, and Trump campaign chairman and former Breitbart News executive Stephen Bannon as chief strategist.
Mr Bannon's appointment has proven controversial due to his connection with the right-wing news site, with increasing calls from Democrats and activists for Mr Trump to rescind the appointment.
The President-elect posted on Twitter overnight to comment on the process, although faced some criticism after he referred to the candidates as 'finalists'. Some commentators drew comparisons to Mr Trump's time as the host of The Apprentice reality show.
Very organized process taking place as I decide on Cabinet and many other positions. I am the only one who knows who the finalists are!— Donald J. Trump (@realDonaldTrump) November 16, 2016