Friday's weigh-in also confirmed a significant size difference, with Joshua tipping the scales at 17 stone 8 pounds (111.5 kilogrammes) compared to the 39-year-old Povetkin's 15st 12lbs.
"Coming back is a blessing - it's time to put on a performance", said Joshua at a Wembley news conference on Thursday.
Joshua knocked out Klitschko at Wembley in April 2017 and the 2012 Olympic champion has not fought at the stadium since then.
Joshua, who is undefeated in 21 fights - 20 of which he won through knockouts, added the WBO world heavyweight title to his collection when he beat Joseph Parker by unanimous decision in March at the Principality Stadium in Cardiff. I've come to a stage now where I have a deep world and my hearts big.
"Povetkin is unsafe", Joshua said in the build-up to tonight's fight. Every week we have a live Cord Cutting Q&A, and weekly Cord Cutting recap shows exclusively on our YouTube Channel! He is one of the lightest heavyweights but that means he has speed.Povetkin, speaking through a translator, said: "I think I am in very good shape, I've had a good camp".More news: See Joaquin Phoenix in full Joker movie makeup
More news: Sergio AGUERO renews contract until 2021 with Manchester City
More news: Coca-Cola eyes move into cannabis drinks
"And I'm expecting the same type of fight because..." Joshua has promised a breaking down job, the crowd will want a knockout and Povetkin will be determined to crash the Wembley party. My coaches wonder what I'm doing in sparring, so sometimes I'll tell them to hit me because I know how to throw punches.
"Go out there - he strong to the head, whip him to the body, he strong to the body I'll whip him to the head".
"I'm up against one of the best fighters in the world".
"It's Chapter Two to a certain degree but I just feel relaxed and calm. I work alongside people who have the same strengths".
The Povetkin clash was agreed on after both camps of Joshua and WBC world heavyweight title holder Deontay Wilder failed to agree on talks for a unification fight.