Breazeale may be first in line for his title shot, but WBC president Mauricio Sulaiman made it abundantly clear that he wouldn't prevent the victor of Wilder/Fury facing Joshua in a unification fight, should a deal be agreed.
And the Briton has taken that advice on board, with Sulaiman confirming that Fury has now signed up.
The voluntary enrolment means fighters can be tested outside the competition timescale and boxers can also take part in an awareness programme "to educate and prevent boxers about the dangers of substances and the tragic effects that they can lead to".
The fight will be the biggest heavyweight showdown since Anthony Joshua's fight with Wladimir Klitschko and is likely to be the biggest test of Wilder's career so far.
Wilder, who will be making his eighth title defense against Fury, had three fights in 18 months impacted by his opponents' positive VADA drug tests.
"It's very quick to start up the program", DiBella said.
"We wrote to (Wilder's camp) after our fight with Povetkin and said we need to make our move soon because of mandatories in place for April 13, so could we have a meeting", Hearn added. Everything will get worked out this week now that the paperwork is in and then the testing can start.
Both men are undefeated in their professional careers, Wilder boasts an incredible 40 wins, 39 KOs, whereas Fury is 27-0 with 19 KOs and a more star-studded CV to match. Fury eventually accepted a backdated two-year ban from UKAD.