Anthony Joshua says he is "ferocious, hungry and determined" as he prepares to face Wladimir Klitschko at Wembley on Saturday.
Joshua was speaking at a news conference at Sky HQ days before he is due to defend his world heavyweight title against former champion Klitschko.
He said he had worked hard for this latest fight.
"I'm still up very early in the morning and staying up very late at night to prepare mentally and physically," he said.
"This is another stepping stone towards greatness. I've never shied away from any fight. Let's rock and roll.
"I am a young lion, ferocious, hungry and determined. When I wrap it up, it's a win."
Klitschko revealed he has recorded his prediction for the fight on a memory stick which will be sewn into his robe, to be sold to raise money for his Klitschko Foundation.
He joked he was not Nostradamus but: "I'm determined and looking forward to it."
Joshua won Olympic gold in London in 2012, 16 years after watching in awe as his opponent achieved the same feat in Atlanta.
If local support counts for anything, Joshua will be fine.
A man who once spent two weeks on remand in Reading jail ("for fighting, crazy stuff") has turned his life round to the extent that children at his old school in Watford talked this week of him giving them "something to aspire to".
Is he - as some experts contend - still too raw as a boxer? He has won all 18 fights as a professional by knockout, but Klitschko's trainer Johnathon Banks warns: "You can't buy experience."
Britain's former world champion Lennox Lewis, who retired after winning a bloody battle against Klitschko's brother Vitali, was among the media throng here, working for German TV.
"You don't want to be learning in big fights like this," he said, but was unable to predict which way it will go.