Prince Harry already has big plans for his new nephew.

Speaking with reporters at the Sentebale "Stories of Hope" exhibition opening on Thursday, Prince William's younger brother joked that he'll make sure his nephew, Prince George of Cambridge, "has fun."

Upon hearing that, the Queen immediately declared war on Las Vegas.

"It's fantastic to have another addition to the family," Harry said, noting that the newborn was crying when they first met. "I only hope my brother knows how expensive my babysitting charges are."

According to Us Weekly, the event marked Harry's first public appearance since his sister-in-law Kate Middleton gave birth to Prince George on Monday. The event was for the royal's Sentebale charity, which helps children affected by poverty and the HIV/AIDS epidemic in Lesotho, Africa.

"Sentebale really shows Harry's attitude to children and what he cares about," royal photographer Chris Jackson, whose photos make up the exhibit, told Us Weekly. "His new nephew -- who is an incredibly privileged child and will grow up in a certain kind of world -- he loves and will be a great uncle to. But these kids matter to him, too. He relates to them and wants to do something for them."

"Harry feels at his most relaxed around kids," Jackson said. "Like Princess Diana, he has his mother's charm and sense of humor. There are none of the usual royal barriers with these kids; he can be natural. It's perhaps one of the only places where he really can be himself."

Contact Tony Hicks at Facebook.com/BayAreaNewsGroup.TonyHicks or Twitter.com/insertfoot.