Anthony Joshua says his protege Lawrence Okolie must overcome a severe test of character in an "epic" fight with Isaac Chamberlain.

The cruiserweight duo will settle their rivalry this Saturday night at The O2, live on Sky Sports, and Joshua will be watching from ringside as his management company are guiding the career of Okolie.

Joshua remains confident that Okolie will emerge with victory in a battle of unbeaten Londoners, but admits the 25-year-old could be dragged into a gruelling battle.

"When you are the power puncher and expected to KO everyone in round one or two, and then you find someone who is making you miss, it makes you question yourself," Joshua told Sky Sports.

"In terms of predictions of who is going to win, I'm going to say Lawrence because that's my guy.

"But in terms of how the fight will go, I think it will be epic and phenomenal, because they are going to push each other past round six, round eight, and go into the championship rounds."

Chamberlain honed his defensive skills in past sparring sessions with Joshua and Deontay Wilder, a fellow world heavyweight champion, and AJ suggested that Okolie may have to prove his mental and physical strength.

"Isaac is very experienced, sparred world champions," said Joshua. "He's sparred myself, sparred Wilder, and he knows how to make these big punchers miss.

"Lawrence is very gutsy, rangy, been an Olympian. He's been hurt, he's hurt opponents, so when he goes to those later rounds, he'll be able to question himself once again.

"That's what I find interesting about this, and that's why I haven't put a prediction on what round it will go, but I do know it will be an interesting and tough fight."

Watch Lawrence Okolie vs Isaac Chamberlain, from The O2, London, Saturday, February 3, live on Sky Sports Main Event & Action.