NEW YORK (AFP) - Britain's Prince William met US President Barack Obama in the Oval Office on Monday as well-wishers braved the freezing cold to glimpse his pregnant wife, the Duchess of Cambridge, in New York.
The royal pair parted company on day two of their second visit as a couple to the United States as they mix diplomacy with supporting their favourite causes and promoting British business.
William, wearing a dark suit, blue shirt and red tie, discussed illegal wildlife trading with Obama in a meeting hailed as a coup for the prince by British commentators.
Second in line to the throne after his father Prince Charles, the visit sees William doing more long-haul work for the British monarchy as Queen Elizabeth II approaches her nineties.
Obama is reportedly an ardent admirer of William's grandmother, who hosted America's first couple for a state visit in 2011, when the US president last met the 32-year-old British prince.
Obama and William, known officially as the Duke of Cambridge since his wedding in 2011 to long-term girlfriend Kate Middleton, spoke to each other but did not address the press.
William flew to Washington DC without Kate, who is five months pregnant with the couple's second child, and will address the World Bank on illegal wildlife trading after meeting Obama.
A Buckingham Palace representative said he flew first class on a commercial shuttle from New York, where his wife delighted a small group of well-wishers outside a local child development centre.
Catherine, Duchess of Cambridge (right), and New York City Mayor Bill de Blasio's wife Chirlane McCray (left) greet guests at Northside Centre for Child Development in New York City on Monday. -- PHOTO: AFP
Kate, who is due to give birth in April, wore a black coat by British label Goat called Washington, embellished with nude tabs on the cuffs and at the back, and finished with a nude collar.
Kate, who is travelling with her personal hairdresser, wore her auburn hair gently waved and half swept from her face to show off her coat, which retails at 680 pounds (S$1,403), to full effect.
She was welcomed at Northside Centre for Child Development in Harlem by a beaming Chirlane McCray, wife of New York mayor Bill de Blasio, who wore an elegant purple coat.
"Ready to talk mental health and child development with The Duchess of Cambridge," she tweeted before the event.
The duchess and McCray were to take part in gift-wrapping with volunteers and meet students undertaking a craft-making exercise.
Kate is then due at a lunch with successful British expats at the British consul general's residence.
In the evening William is due to attend a conservation reception with former US secretary of state and expected 2016 presidential contender Hillary Clinton and her daughter Chelsea.
The couple will attend then their first NBA basketball game when they will see LeBron James and his Cleveland Cavaliers visit the Brooklyn Nets.
The four-time NBA Most Valuable Player nicknamed "King James" said it would be a honour to lead the Cavaliers in search of their seventh win in a row at the Barclays Centre before royalty.
"You read about people like them only in books growing up," James said. "To hear that they're coming to town to see me play and they want to see me do what I do best, it's a huge honour."
The couple are in the United States without their one-year-old son George and are expected to fly home as soon as their last function concludes on Tuesday night.
They are staying at the Carlyle Hotel, where William's mother Diana used to stay, and where jubilant royal watchers cheered as they stepped out of their presidential-style motorcade on Sunday.
Their arrival has drawn comparisons with the 1985 visit made by Charles and Diana, when the princess dazzled Americans by dancing with US president Ronald Reagan and Hollywood star John Travolta.
It marks only their second tour outside the Commonwealth family of nations, a visit expressly made on behalf of the British government rather than Queen Elizabeth.
Despite their privileged upbringings, it also marks the first time that either William or Kate have been to New York.
Their visit coincides with days of protests demanding justice for black men killed by white police officers.
On Monday, a small number of demonstrators briefly blocked morning rush hour traffic on the Verrazano Bridge, which connects Staten Island to Brooklyn.
The protesters ran out onto the highway with black banners written with the names Eric Garner and Mike Brown, who died at the hands of police, and "This Stops Today".