The Duke and President Obama spoke about the new royal baby, due next year, with William joking that he was so excited when Prince George was born he "forgot" to ask whether he was a boy or girl.
"Last time, I remember when George was born, I forgot to work out whether it was a boy or a girl," he revealed. "The excitement of the event and everything else was just chaos. You are suddenly... well actually it's a boy. So now, it's good."
"It's going to be interesting next year. A busy year next year," he added.
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In true British style, the Duke of Cambridge arrived early at The White House, and was given a tour of the famous building by Vice-President Joseph Biden and his wife Dr Jill Biden ahead of his meeting with President Obama.
William and Kate previously met Barack Obama when he and his wife Michelle visited London in May 2011. However Kate remained in New York on Monday to tour a child development centre with the city's First Lady Chirlane McCray.
Following his morning meeting at The White House, the Duke of Cambridge joined First Secretary of State and Leader of the House of Commons William Hague for the International Corruption Hunters Alliance Conference at the World Bank.
The duo previously worked together at the London conference on the Illegal Wildlife Trade in February 2014, which was also attended by William's father, Prince Charles, and brother Prince Harry.
Prince William then spoke at a conference about fighting the illegal wildlife trade
The issue of illegal wildlife trade is close to William's heart and he joined forces with David Beckham to launch the #WhoseSideAreYouOn campaign earlier this year.
The Duke joined the World Bank Group President Jim Yong Kim at the opening session to address more than 300 corruption experts, heads and senior members of anti-corruption and prosecuting agencies; and representatives of international organizations from more than 120 countries.
William will return to New York on Monday evening to resume his engagements in the Big Apple. Accompanied by Hillary and Chelsea Clinton, William will attend The Conservation Reception, an event co-hosted by the Royal Foundation and the Clinton Foundation in recognition of the work carried out by United for Wildlife, Tusk Trust and its US partners.
The Duke is then due to reunite with Kate at an NBA game on Monday night, which is also expected to be attended by Beyoncé Knowles and Jay Z.