Paul McCartney has brought joy to people through his music for decades, so it's no wonder nine-year-old Harrison Haines, named after another famous Beatles member, wanted advice on how he too could change the world.

"Go to school ... and just be good to people. Learn a lot about the world, and where there's issues that you think need changing, just be very strong and go and change them," McCartney sagely replied.

Paul McCartney meets Perth fans. Credit:9 News Perth

Appearing in Australia for the first time in 24 years, McCartney held an intimate Q&A with 20 lucky fans in Perth on Thursday, shaking their hands as many squealed with delight and held back tears of happiness.

Reminiscing about the Beatles' famous visit to Adelaide in 1964, McCartney said it was a phenomenal experience and the band felt like royalty.