Andy Ruiz Jr shows off new look as he warns Anthony Joshua

ANDY RUIZ JR has warned Anthony Joshua he will be "lighter, faster and more powerful" for their rematch on December 7 in Saudi Arabia.

The Mexican was billed as a no-hoper when he came in at short notice - and weighing 19st - to challenge AJ for his world titles in June.

Andy Ruiz Jr is already looking in better shape as he counts down to his AJ rematch

Andy Ruiz Jr came in heavy for the first scrap - but still shocked the world

But Ruiz Jr delivered one of boxing's biggest ever shocks to floor Joshua three times on the way to a seventh-round KO triumph.

Now the two will get it on all over again in the desert - and Ruiz is promising an even tougher night for the Brit.

Speaking to ESPN Deportes, Ruiz said: "I have a lot of respect for Anthony, outside the ring he is a very good man.

"But inside [the ring] there are no friends, there is no respect or anything.

"It will not be an easy fight. I think it will be a hard fight, but nothing is easy in life, so we are training very hard. We will be prepared for whatever he bring.

"I will arrive in better condition.... lighter, faster and more powerful. They will believe that in December they will win.

"People will always talk like this, but I have faith that we're going to win and shut up more mouths."

Fans were last month convinced the WBO, WBA and IBF heavyweight world champ had PUT ON more weight during a training session out in Diriyah.

But recent clips and photos from his camp show a leaner and meaner looking Mexican.

And he has also revealed he has swapped his snack of choice, Snickers, for healthier options like fruit and nuts.

Joshua has also promised to showcase a different physique for his big night out in the Middle East.

And his fans are already purring at what his trimmed-down new look after he showed it off during a workout in Saudi.

One said: "Joshua looks a lot better now he's shedded the weight. Like he just wanted to pose for Instagram before."

A fellow user wrote: "Yes AJ. The 2014/15 lean, mean, hook-wielding, uppercut-throwing machine is back by the looks of things."

Another commented: "Anthony Joshua cutting plenty of weight for his rematch with Andy Ruiz Jr is absolutely what's needed."

A fellow user posted: "AJ appears to have lost some muscle mass which is great, he was better when not as big."

Another comment read: "AJ was way too heavy for the first fight. This time he's already shaved all that muscle off. Light work this time, he's going to ruin Ruiz."

One wrote: "Anthony Joshua has lost a lot of muscle mass, which he needed to do."

In reply to a photo Joshua posted, another fan said: "Brother looking lean... muscles disappearing. Thank goodness."

The world of boxing was left stunned as Anthony Joshua was battered by Ruiz back in June