Joshua and Parker will on Saturday, March 31 clash in a unified bout at the Principality Stadium in Cardiff.
Joshua will have to defend his WBA and IBF titles while Parker is bringing his WBO belt to the fight.
Ahead of the bout, both fights weighed in for their title unifier and Joshua was at 17 st 4lbs, almost 12 lbs down from when he beat Carlos Takam in October 2017.
Parker weighed in at 16 st 12 lbs, 9 lbs less than when he beat Hughie Fury in September 2017.
“Taking that bit of weight off makes this fight a little easier,” Joshua said.
The boxers also did the ceremonial final stare down after their weigh in.