Former UFC heavyweight champion Ngannou, who will fight Joshua at Riyadh's Kingdom Arena, made his pro boxing debut last October when he lost on a split decision to WBC world champion Tyson Fury in a non-title bout.
Ngannou almost delivered an upset when he dropped Fury to the canvas with a left hook in that fight.
"I heard that he doesn't have a chin," Ngannou said of Britain's two-times world champion Joshua.
"I don't know if it's true or not. We're going to find out. I hope I have the opportunity to test that out, that's my wish."
The fight takes place three weeks after Fury takes on Ukraine's WBA, WBO, IBF and IBO champion Oleksandr Usyk for the undisputed heavyweight title in Riyadh.
Joshua lost his belts to Uysk in 2021, and was also beaten in a rematch.
Co-promoter Frank Warren suggested the winners of the February and March fights could go on to meet later in the year.
"For the winner - the big fight's happening on February 17, with Tyson and Usyk," he said. "The winner of that, would we like to see them with the winner of this fight? Everybody in boxing would love to see that."
Chinese heavyweight Zhilei Zhang and New Zealand's Joseph Parker, who beat former champion Deontay Wilder last month, will fight for the WBO interim title on the undercard of the Joshua vs Ngannou clash.
