The 'I Kissed a Girl' singer – who is engaged to British comedian Russell Brand – is dying to meet the British prince who she has dubbed 'The Ginger Ninja'.
A source told the Daily Star newspaper: "Katy's really interested in the British royal family. She likes chatting to Russell about them and thinks Harry sounds hilarious as he's got such a wild streak."
Katy's love for Britain's royal family comes from her parents – Christian pastors Keith and Mary Hudson - who were huge fans of the late Princess Diana.
The source added: "She would love to hang out with both the princes this summer. Her parents were huge Princess Diana fans."
Along with meeting Prince Harry and his brother William, Katy also wants to take a look around Buckingham Palace - the home of Queen Elizabeth II, the princes' grandmother.
The source said: "Katy loves the idea of snooping around the palace and seeing where the queen entertains. She said she'd like to go for a traditional afternoon tea at a posh restaurant afterwards."