The mayor of London tweeted he had caught up with his “good friend” Mr Bloomberg, who was in charge of the city from 2002 to 2013 as well being a candidate for the 2020 Democratic nomination for US president.
“Hello from the Big Apple!” Mr Khan tweeted, along with photos including one from the PA news agency’s Stefan Rousseau.
“Great to catch up with my good friend @MikeBloomberg for coffee here in NYC.”
Mr Khan has said he hopes to use the trip, which will also include visits to California, to attract investment to London.
He will also discuss pandemic recovery with senior politicians.
London was hit hard by the coronavirus pandemic, losing £7.4 billion of international tourist spend in 2020 alone.
Mr Khan will launch his new £10 million tourism campaign in New York, alongside mayor Eric Adams.
Mr Khan has told PA he intends to use the trip to “bang the drum for London”.
“We’re doing four regions in four days, New York, Silicon Valley, San Francisco, Los Angeles,” he said.
“It’s really important that I bang the drum for London, that’s what I intend to do.”