Joshua looks to become a three-time world heavyweight champion this weekend as he faces Usyk in their eagerly anticipated rematch.
The Ukraine fighter dominated last time around, winning on points via unanimous decision to become a two-weight world champion.
Usyk is a big favourite heading into the rematch, and now Wilder has backed the pound-for-pound great to defeat Joshua again:
"But this is boxing and you never know.
"I wish them the best of luck and hope they get out of the ring just like they came in - safe and sound."
Wilder's comments have come about the same week in which he announced his return to boxing.
'The Bronze Bomber' has not fought since he was beaten for a second time by Tyson Fury last October.
The American has returned to the public eye in recent months amid talk that he was considering retirement.
This has proven to not be the case though as he has now confirmed that he will face Robert Helenius in his comeback on October 15 at the Barclays Center.
This fight will be shown on FOX pay-per-view in the United States, courtesy of Premier Boxing Champions (PBC).
Wilder has explained why he felt like his job was "not done" in boxing:
"It's been a long journey for me and as of today it continues," Wilder added.
"I thought so many times about whether I should stay out of the business or come back.
"Once I got my statue in my hometown and saw so many people arrive and celebrate with me and my family, to see all the emotions, grown men crying in front of their children and saying, 'He is a real true king,' made me feel like my job is not done.
"So, here I am once again, looking forward to returning to the ring.
"So where all my Bombzquad people at? It's time to put on your war gear. And let's go to work, baby. Bombzquad is back."