Ruiz was spotted giving Joshua’s mother a friendly handshake as the pair smiled and exchanged pleasantries after meal at the Al Faisaliah Hotel.
Joshua was also pictured kissing his mother on the forehead and was seated next to her throughout the evening.
Undercard fighters Dillian Whyte and Tom Little were in attendance while promoter Eddie Hearn gave a speech to guest at the dinner.
Speaking ahead of the big fight, Joshua revealed how he plans to approach Ruiz this time around.
“For me, take centre. If I’m six inches in front of Ruiz, all takes for a man to miss a punch is six inches,’ he told reporters.
“So sometimes you haven’t even got to be running around the ring.
“I asked him upstairs, I said: “How do I beat you, then?” He says: “Maybe, you should move around a little.
“Boxing is a sweet science of the sport. I’m 6ft 6in, so it would be wrong of me to sit in front of Ruiz and go toe-to-toe hooking.
“I’ve got to box to my attributes which is range and movement. My style is not what a scared boxer would do, I think it’s what a smart fighter would do.”
Meanwhile in Friday’s weigh-in, Joshua dropped to lighter than 17 stone for the first time since 2014.
The former world champion is 10lbs lighter than he was during their first meeting in New York in June.
He credited an adjusted training regime for his leaner frame which promises greater stamina and agility.
On his part, despite claiming he will come into the fight in at a similar weight to his victory six months ago, Ruiz tipped the scales at 283.7lbs [20st 2lbs], more than a stone heavier than the 268lbs that he weighed when he stunned Joshua in New York.
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