Joshua posted a video on Twitter confirming the fight for Cardiff as he bids to unify the belts in the heavyweight division. "It's finally done now, so I'm looking forward to getting back to training".
The fight will be the first time in history that two reigning heavyweight world champions have met in the United Kingdom.
But Joshua is paying little attention to talk of Parker's renowned chin as he will instead attempt to break down the Kiwi with the same sustained body assault that grinded down the resistance of Carlos Takam in October.
"I haven't seen them all, but I've heard some of them", Joshua said when asked about the provocative comments coming from Parker which continued in mainstream British media over the weekend. "A couple of months ago I heard him say 'why should I be anxious about this little kid from New Zealand"? And the world is about to find out whether AJ can really take a punch.
The aggressive approach by Parker to flush out Joshua for this lucrative fight has clearly hit a nerve with the big Brit. My entire existence is now devoted to proving what the boxing world already knows'.
"In the last fight I saw with [Wladimir] Klitschko, he got knocked down, got up, showed a lot of heart, so credit to him".More news: Heaps of New Games and Ports Revealed for Switch
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Then last week, it emerged that Parker's promoter, David Higgins, was flying to London to try and seal the deal.
They also offered to pay £10,000 to anyone who could provide further footage. It has been said that he is punching above his weight, but he didn't become WBO heavyweight champion by being lucky.
"But I think I can beat anyone in the world - I would not be here if I did not believe in myself".
Parker's last fight was in England when he defended his WBO title for the second time, beating Britain's Hughie Fury on points in Manchester in September.
The winner is likely to target the victor of the Deontay Wilder and Luis Ortiz fight on March 3, where the former will defend his WBC belt in NY. Wilder, 32, of Tuscaloosa, Alabama, is scheduled to defend his title against top contender Luis "King Kong" Ortiz (28-0, 24 KOs), a 38-year-old Cuban defector fighting out of Miami, on March 3 at Barclays Center in Brooklyn, New York, in a fight that was made official on Friday.