The 26-year-old made light work of Charles Martin earlier this month to claim the title and he will return to the O2 Arena this summer looking to cement his crown.
The London 2012 super heavyweight gold medallist knocked out Martin in the second round and potential opponents for his next fight include the likes of Bermane Stiverne, Eric Molina and Dominic Breazeale.
In a video posted on his official Twitter account, Joshua said: “I’ve been speaking with my coach and I want the closest fight date possible because I’m feeling good.
“I can’t wait to get back into the training camp and pick up where we left off.
“The date to put in your diary is June 25, back at the O2 Arena for my first title defence and a jam-packed undercard.
“I can’t wait to be back and I’m looking forward to performing once again.”
