Klitschko, a 41-year-old who tasted defeat for the first time in a decade when going down to Tyson Fury in November 2015, is hoping to reclaim the WBA and IBF world heavyweight titles he lost that night in Dusseldorf.
For Joshua, this represents an opportunity to score a victory over an established, respected fighter for the first time and silence the sceptics who still question whether he can live up to the hype.
When is it?
The fight will take place on Saturday 29 April at Wembley in London.
What time will it start?
Joshua and Klitschko are expected to enter the ring at approximately 10.00pm.
Where can I watch it?
The main event and the undercard will be shown live on Sky Sports Box Office.
Alternatively, you can bookmark this article, which will become The Independent’s live blog.
Can I still buy tickets for the event?
All tickets, including the extra 10,000 made available after London Mayor Sadiq Khan agreed to increase Wembley’s capacity, are now sold out.
Who’s on the undercard?
Scott Quigg vs Viorel Simion
WBA international featherweight title
Luke Campbell vs Darleys Perez
Katie Taylor vs Nina Meinke
Lawrence Okolie vs Russ Henshaw
Joe Cordina vs TBC
Josh Kelly vs Faheem Khan
What are their records?
Wins, wins by knockout, losses, draws
Joshua: W18 KO18 L0 D0
Klitschko: W64 KO53 L4 D0
What’s on the line?
Joshua is the reigning IBF world heavyweight title holder, a belt that Klitschko lost in defeat to Tyson Fury in November 2015.
Fury was subsequently stripped of the belt after failing to fight mandatory challenger Vyacheslav Glazkov. Charles Martin, who beat Glazkov, then lost his first defence of the belt to Joshua.
The WBA (Super) and vacant IBO world heavyweight titles, both previously held by Fury, will also be on the line.
Who will win?
What are the odds?
Odds provided by 888.com
Joshua decision: 8/11
Joshua by KO: 11/2
Klitschko decision: 3/1
Klitschko by KO: 11/2