The Duke and Duchess of Cambridge have met celebrities including rapper Jay Z and pop star Beyonce as they continue their three-day US tour.

The royal couple sat courtside at the Barclays Centre for the Cleveland Cavaliers' win over the Brooklyn Nets.

William and Kate chatted with the multiple Grammy winners during a break in play.

They also met four-time NBA Most Valuable Player and double Olympian LeBron James before he took to the court.

Outside the Barclays Centre several dozen protesters called for justice for black men who have been victims of police violence in recent months.

James was among several NBA players who wore "I can't breathe" T-shirts as they warmed up for the game to show their support for protests which have been held across the US.

The slogan has been used to call attention to the death of Eric Garner, who died after a New York police officer used a chokehold during an arrest in July.

The Duke and Duchess of Cambridge began their whirlwind US visit with separate stops in Washington and New York on Monday.

Prince William sat with President Barack Obama at the White House, while Kate visited a child development centre in Harlem.

As reporters crammed into the Oval Office to snap photos, William could be heard discussing the "excitement" surrounding the birth of his son George in 2013.

He confessed to Mr Obama that in the "chaos" of the delivery room he forgot to ask if Prince George was a boy or a girl.

"I remember when George was born I forgot to actually work out whether it was a boy or a girl," William was heard telling the President as the two shared pleasantries.

He added that he expects 2015 to be a "busy year", when Kate is due to give birth to their second child.

Kate, who is five months pregnant, landed in New York with her husband on Sunday night. The two were greeted by cheering crowds as they arrived at their Manhattan hotel.

Following his stop at the White House, William delivered remarks on wildlife trafficking at the World Bank in Washington.

He called the practice "one of the most insidious forms of corruption and criminality in the world today".

William announced a taskforce - to be chaired by former British Foreign Secretary William Hague - that will work with the transport industry to combat the illegal, multi-billion dollar trade.

"Our collective goal must be to reduce the wildlife trade by making it harder: denying traffickers access to transportation, putting up barriers to their illegal activities, and holding people accountable for their actions," he said.

The royal couple have a hectic schedule for their three-day visit, including a stop at the National September 11 Memorial and Museum.

There is also a night of glamour planned at a black-tie, scholarship fundraiser for the University of St Andrews, where the royal couple met and earned degrees.

(sky news)