A record-braking crowd of 90,000 will cram into Wembley Stadium for what is set to be a historic night under the arch.
Joshua is determined to prove he can step up to elite level just three and a half years since turning professional.
But the old master - Klitschko - stands in his way. The Ukrainian lost his titles to Tyson Fury last time out and is aiming to set the record straight by reclaiming his crown at the ripe old age of 41.
Expect fireworks as the two man mountains collide.
Scroll down for everything you need to know ahead of the big fight....
Date, time & venue
Joshua faces Klitschko at Wembley Stadium on Saturday 29 April.
Where to watch
The fight will be broadcast live on Sky Sports Box Office for a price of £19.95. Coverage starts at 6pm. Click here for more information.
The main event is expected to start at roughly 10pm but, as with all major boxing shows, could be subject to delays.
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Josh Kelly vs TBC
Lawrence Okolie vs Russell Henshaw
Katie Taylor vs Nina Meinke (WBA Inter-Continental Lightweight Championship)
Luke Campbell vs Darleys Perez (WBA World Lightweight Championship Eliminator)
Scott Quigg vs Viorel Simion (WBA International Featherweight Championship)
Main event: Anthony Joshua vs Wladimir Klitschko (IBF, IBO and WBA Heayvweight Championships)
What they're saying
Anthony Joshua: "Age plays a role. He said himself he’s old enough to be my dad. I won’t let that be the reason I win, though.
He’s going for his legacy, he wants his title back and it’s an amazing opportunity for me.
"I can box Klitschko for 12 rounds, make him miss, make him pay, don’t get hit — I can deal with him, trust me."
To my supporters, I thank you for your part in my journey. God bless 🖤 pic.twitter.com/Vao15HbGfj— Anthony Joshua (@anthonyfjoshua) April 26, 2017
Wladimir Klitschko: “All the pressure is on the other side, not on me. I don’t need to defend my titles, I don’t need to [worry about] losing a winning record.
“I just want to enjoy myself in the ring, enjoy the atmosphere, enjoy my performance.
"I want to impress myself, and my knowledge of what I am capable of doing."
Tale of the tape: Scroll over the interactive image below
Odds (via 888Sport)
Joshua to win: 2/5
Klitschko to win: 2/1
Odds correct as of 5pm April 27.