Eddie Hearn says Anthony Joshua needs to stop feeling sorry for himself as the build-up begins ahead of his rematch with Andy Ruiz Jr.

Joshua recently admitted he had 'lost a bit of passion' for boxing after failing to secure mega-fights with heavyweight rivals Deontay Wilder and Tyson Fury.

The 29-year-old was stopped by Ruiz Jr in a shock defeat in New York on June 1 and will face the Mexican for a second time in Saudi Arabia in December.

Eddie Hearn (pictured) has told Anthony Joshua to stop feeling sorry for himself

Joshua recently admitted he'd lost a bit of passion for boxing after failing to secure mega-fight

Hearn believes the public will see a 'nasty' side of Joshua in his rematch with Ruiz Jr

Hearn has now urged Joshua to sharpen his focus as he prepares to start his training camp and is confident his fighter will refind his hunger for the sport.

'I think he's just got to snap out of it,' Hearn said to Sky Sports.

'I think he was disillusioned with the sport because he wanted to fight Deontay Wilder.

'He couldn't get that fight and as he said in the interview, he didn't really want to fight Andy Ruiz. But tough, you fought him and you fought a real hungry guy.

'I think the great thing about this promotion is that now, for the first time next week, he looks a man in the eyes who is the only man to beat him as a professional.

'It's going to be absolutely huge. The whole world will stop to watch this fight.'

Joshua has been criticised for underestimating Ruiz Jr ahead of their first fight, which saw the Watford-born heavyweight allow his foe to pose with his four heavyweight belts at the pre-fight weigh-in.

With Ruiz Jr now the proud owner of the IBF, WBO and WBA belts, Hearn has warned the Mexican to expect a very different Joshua in the rematch.

'He ain't going to be giving Ruiz no belts to hold because he doesn't have them anymore,' said Hearn.

Hearn believes Joshua wants to knock Ruiz Jr 'clean out' following his loss in June

Joshua has been licking his wounds since being stopped Ruiz Jr back in June

'He doesn't even want to talk to him, he wants to knock him clean out. He didn't have that feeling last time but it's a new game now, a new game. Josh wants to take his head off.'

Joshua has been embroiled in a war of words with former heavyweight world champion Lennox Lewis and branded him a 'clown' for criticising him after his defeat in June.

Hearn has welcomed Joshua's change in character and expects the public to see a very different side to his personality over the coming months.

'He's thinking "I've tried to be the role model, I've tried to be that guy but people have slagged me off and said what they want to say – now I'll say something back".

'Now he gets criticised for calling people things, like Lennox Lewis who has criticised him and given him sly digs his whole career.

'Josh can't win so he's decided, do you know what, maybe it's a new approach, bring back the nasty Josh. We hope that nasty Josh comes out for the Ruiz fight.'