The heavyweight duo will lock horns at the Manchester Arena, with promoter Eddie Hearn confirming “the deal is there”.
Joshua’s IBF belt and potentially Tyson Fury’s vacated WBO and WBA titles will be on the line.
Troubled Fury was earlier this week banned from fighting by the British Boxing Board of Control after he admitted taking cocaine.
And he withdrew from two scheduled fights with the 40-year-old Ukrainian.
But now that slot has been filled by Joshua, 27, who is undefeated in 17 fights and was pencilled in to defend his crown for a second time at the end of November.
Hearn told BBC Radio 5Live: “The deal between the fighters is there. The financial terms are agreed, there was a problem with US broadcasters but that has been sorted.
“It is now a case of getting the paperwork and the sanctioning in order. Hopefully in a couple of days we will have the official announcement.”
And David Haye has backed Joshua to end the Klitschko era once and for all.
He said: “I definitely think the era of the Klitschkos will be over.
“Joshua has got him at the perfect time. Klitschko physically always looks the part and comes to the ring in shape but he is not the fighter he once was.
“And sometimes fighters are the last to realise it. I just hope he doesn’t get too bashed up.
“Joshua at 26 is too fresh, too young, too enthusiastic. Klitschko is just too old.”
