Unbeaten champions Parker and Joshua will unify their WBO, WBA, IBF and IBO belts next weekend at the Principality Stadium in Cardiff.
The 26-year-old Parker knows he is the underdog heading into the biggest fight of 2018, but speaking to reporters at his first press conference since arriving in the UK, the Kiwi is motivated by the fact he thinks "the public are underestimating my team and me".
"They're basing it on my last three fights and see Joshua as unbeatable but I have an element of surprise," he added.