The Watford native will face unbeaten American Dominic Breazeale (9/1) at the O2 in London – the same venue where AJ won the title with a second round stoppage of Charles Martin on 10 April.
Thirty-year-old Breazeale has won all 17 of his professional fights, 15 of those coming inside the distance.
Breazeale, who previously played quarter-back for the University of North Colorado, was the number one ranked amateur in the US ahead of the 2012 Olympic Games in London but suffered a surprise loss to Russian Magomed Omarov in the prelims. Anthony Joshua, famously, went on to win the gold medal in the same super heavyweight division that year.
Joshua, who is 16-0-16 KO’s, said on twitter after the fight was announced “2 undefeated fighters going 2 war June25! Vs Dominic Breazeale at the den [O2 Arena in London] in front of home support & explosive undercard.”
Joshua is rated a 1/10 shot by the bookies to win by KO.
“AJ has pummelled his 16 previous opponents and all signs point to knockout number 17 on the 25 June,” said William Hill spokesman Tony Kenny
Should Joshua defeat Breazeale then there are some big fights awaiting the golden boy of British boxing. William Hill make Joshua 8/11 to beat Tyson Fury and 4/7 to beat David Haye.
Latest Big Fight odds from William Hill
1/20 Antony Joshua, 33/1 Draw, 9/1 Draw
1/10 Anthony Joshua to win by KO
Undercard at the O2 on the 25 June
4/9 George Groves, 25/1 Draw, 7/4 Martin Murray
Joshua potential fights
4/7 Anthony Joshua, 25/1 Draw, 11/8 David Haye
8/11 Anthony Joshua, 33/1 Draw, Evs Tyson Fury
