Both men go in to the fight undefeated and both are putting their respective titles on the line. Anthony Joshua has himself a credible contender and it's going to be Box Office.
Can Joshua take all three belts and take his record to 21 wins from 21 bouts? Will he keep his knockout record too, or can Parker spring the surprise to end all surprises?
The New Zealander is throwing the majority of the jab work as they open up, with both fighters deciding just to take a good, hard look at each other.
Joshua pushes Parker towards the ropes and lands a nice right hand to put the WBO holder under pressure. Joshua finishes strongly with a left hook and a body shot as he stands central in the ring and works his opponent around in circles.
There's a slight bit of blood to the nose of Parker already and he is struggling to get in close to Joshua, who is holding him off with a perfect jab. Joshua's reach is causing all sorts of issues for the New Zealander as he finds it difficult to get in tight on the towering Brit.
It doesn't stop him from throwing a few power moves, though, but Joshua keeps up a high guard and looks untroubled. His physical advantages are already telling here as his reach and height have Parker backing off as Joshua drills a lovely combination.
The Brit still looks only in second gear but he lands another great combo to leave Parker looking slightly jaded after three. Joshua's speed and power looks devastating at the moment, he's moving with remarkable speed.
Parker is in no-man's land on the outside here and is paying for it at the moment. Joshua continues with more comfortable and correct work from the centre of the ring, pushing Parker about and working off his jabbing left.
Joshua is likely four ahead already. A few good combos give the visitor some confidence as he goes rugged into his opponent, but Joshua is soon back at it with continual strong jabbing with his left.
Parker finally sets himself with some nice movement and causes Joshua to miss. A very close round, but one that will be a big confidence booster for the New Zealander. They both get as good as they give, though, and Joshua soon comes back with a monstrous right hand that catches Parker off guard.
Both fighters are applying the gas now. Parker looks quite happy with his work as he ramps up the speed with some effective combinations to finish the round off. The referee gives Joshua a talking too after a late upper cut, but there's no penalty despite the slight break.
The official might just be breaking these men a little too early at times. If it's going to be a reins fight, it'll surely favour Joshua.
Parker is continuing to be backed up on the jab, but he does not look too concerned. This is tight!
This is a boxing match, you know Joshua is slowing down slightly in the eighth and Parker looks nicely set for this pace in the final few rounds. Finally, Joshua moves in with a beautiful left hand and Parker is forced to eat it all.
Far too much breaking up from the referee in this match, though. AJ is back into the centre of the ring again and is now working the jab comfortably again.
Joshua is complaining of a head-butt and he is soon back in his corner having his gloves strapped again. The crowd get behind their man but he is growing frustrated. Parker's hand speed comes alive, but it is hard to tell whether they're scoring shots or not. I just about have Joshua ahead now, but it's very close and you cannot account for subjectiveness in this game.
Nothing too special from Joshua here as he continues to work off the left jab, and it's stopping Parker from finding much of a rhythm. No signs of Joshua gassing though, he looks fit and healthy heading into the final three rounds. Joshua starts to threaten some big ones as a huge left just misses.
Finally some fireworks, but nothing major still. ROUND 11 More strong jabbing from Joshua and it's still keeping Parker at bay whenever he tries to find the inside, he isn't being helped by the referee either who is far too quick on the draw. Still no big moves from either man, just plenty of neat footwork from both men.
Both men exchange strong hooks to end the round, but this is definitely going the full distance. Signs of pockets of fire, but once again nothing gets into motion.
It's still penetrating and scoring points on occasion. Parker needs to take the risks in my book and he tries to open up with a combo that sees Joshua clench his way to safety. Joshua registers a few on the body from range just as Parker drops off and lets him in. Joshua finishes strongly by pushing Parker to the ropes.
Joshua finishes up pushing his man onto the ropes with more probing jab work. Awful refereeing really, he has stopped this fight from evolving.
It's going to points, we'll bring the the judges scorecards as soon as they come in. Joshua looks likely to have this in the bag, but you never know