The Mexican-American underdog shocked the world when he knocked out AJ to claim the WBA, IBF and WBO belts on June 1, though the Brit has now activated his rematch clause and is determined to secure revenge.
Joshua is not the first British star to fight in Saudi Arabia as past year Callum Smith beat George Groves to become the WBA super-middleweight champion and win the World Boxing Super Series.
Ruiz, an American, had insisted that the rematch take place back in the US or at a neutral venue.
Although Eddie Hearn announced the Anthony Joshua vs. Andy Ruiz Jr. rematch as being official, it now appears that is not the case.
In the seventh, Ruiz Jr dropped Joshua twice more, and the referee made a decision to stop the fight.
"Sources tell The Athletic Andy Ruiz Jr. isn't expected to sign off on the rematch in Saudi Arabia unless he's guaranteed a significantly higher purse than the approximately $9 million he's guaranteed to fight Anthony Joshua again".
"Despite some long-overdue reforms on women's rights, Saudi Arabia is now in the grip of a sweeping human rights crackdown, with women's rights activists, lawyers and members of the Shia minority community all being targeted".
"Despite some long-overdue reforms on women's rights, Saudi Arabia is now in the grip of a sweeping human rights crackdown - with women's rights activists, lawyers and members of the Shia minority community all being targeted".
Felix Jakens, Amnesty International UK's head of campaigns, called for Joshua to "inform himself of the human rights situation and be prepared to speak out about Saudi Arabia's abysmal human rights record".
"There's been no justice over the gruesome murder of Jamal Khashoggi, and the Saudi-led military coalition in Yemen is carrying out indiscriminate attacks on homes, hospitals and market-places with horrific consequences for Yemeni civilians".