Ruiz Jr weighed in at 268lbs before knocking Joshua out, but is hoping to be around a stone lighter this time.
“I have a lot of respect for Anthony, outside the ring he is a very good man,” the champion told ESPN Mexico.
“But inside [the ring] there are no friends, there is no respect or anything.
Ruiz is out to silence the doubters once again
“It will not be an easy fight. I think it will be a hard fight, but nothing is easy in life, so we are training very hard. We will be prepared for whatever he brings.
“I will arrive in better condition. Lighter, faster and more powerful. They will believe that in December they will win.
“People will always talk, but I have faith that we’re going to win and shut up more mouths.”