Of course he can't really count himself as the Number 1 fighter until he takes on two others who feel entitled to walk around and call themselves the best Heavyweight in the world. The first is Deontay Wilder, who will be at ringside but likely setting up a WBC defence against Tony Bellew for Autumn, while the other is Tyson Fury, the lineal World Champion, who is back after a long fight against depression and other personal decisions.
Those fights are for another day though as a defeat in this one will reset the Joshua bandwagon, while his opponent Wladimir Klitschko is trying to prove that his defeat to Tyson Fury was nothing more than a 'bad day in the office'.
It makes it an intriguing fight on Saturday with the two men both having plenty on the line, while you can't argue against the interest in the fight which has seen 90,000 tickets sold to event at Wembley Stadium.
The undercard isn't much to write home about and the main event is expected in the ring no later than 10pm UK time in what should be another huge boxing occasion for fans in this country.