The British heavyweight superstar posted two pictures of himself looking relaxed on a beach.
It is not clear when and where the snaps were taken, with AJ expected to be in the UK to announce his rematch against Usyk.
Promoter Eddie Hearn is braced to confirm the heavyweight sequel, set for August 20 in Saudi Arabia.
Joshua, 32, was beaten by Usyk, 35, last September but activated his right to an immediate rematch.
But this time around he will be cornered by esteemed US coach Robert Garcia.
Long-time trainer Rob McCracken has been replaced with Garcia and No2 Angel Fernandez tasked with rebuilding AJ’s confidence and helping him regain his belts.
Promoter Eddie Hearn told SunSport: “He’s as confident as I’ve ever seen him, Anthony Joshua.
“And we all truly believe he will beat Oleksandr Usyk and Robert Garcia is a great addition to the team.”
Hearn believes if AJ continues to roll back the clock and rediscover his ruthlessness, it will lead him back to the heavyweight summit.
He said: “It’s not that I can’t see him losing, but if he does what he knows he needs to do now – and it’s not that he didn’t know what to do in the first fight – but he second guessed himself a lot.
“He tried to adapt a style to beat Oleksandr Usyk which was ultimately a terrible idea.
“Now it’s just like, be you in that ring and you will win that fight.”
By Jack Figg – The Sun