(CNN) - Rory McIlroy says "morality" issues are largely behind his decision to avoid playing in next year's European Tour event in Saudi Arabia.
He joins 15-time major winner Tiger Woods in not taking up an invitation despite reportedly being offered a huge appearance fee, thought to be $2.5 million.
The Northern Irishman said such a tournament did not "excite" him and suggested Saudi Arabia's ongoing human rights issues were also to blame.
"One hundred percent, there's a morality to it as well," the world No.2, who did not deny the reported appearance fee, told the Golf Channel Monday.
"You could say that about so many countries, not just Saudi Arabia, but a lot of countries that we play in that there's a reason not to go, but for me, I just don't want to go."
Saudi Arabia has hosted a number of high-profile sporting events recently, but there are fears such occasions are examples of "sportswashing" -- where governments use major events to divert attention away from human rights issues. It follows the murder of journalist Jamal Kashoggi, who an independent report said was killed by officials working on the behalf of the state of Saudi Arabia.
"We've increasingly seen Gulf countries seek prestige and bolster their international reputations by hosting major sporting events," Adam Coogle, Middle East researcher for Human Rights Watch, told CNN ahead of Joshua's fight.
"Unfortunately, many of these sporting events take place without these countries addressing the root causes of their reputational problems such as longstanding and systematic human rights abuses against political dissidents and activists, foreign migrant workers, and women."
McIlroy said he had no problem watching Saturday's fight, but said he would prefer to turn out for PGA Tour events in the US instead of traveling to Saudi Arabia himself.
"I think the atmosphere looks better at the events on the west coast [of America] and I'd much rather play in front of big golf fans and play in a tournament that really excites me," he added.
World No.1 Brooks Koepka and Phil Mickelson are among the big names set to compete at the Saudi Arabia event, which is due to start on Jan. 30, 2020.