Former heavyweight champion Andy Ruiz Jnr shows off remarkable body transformation as the Mexican gets ready to return to the ring

Former heavyweight world champion Andy Ruiz Jnr has shown off an incredible body transformation on social media as he prepares to step back into the ring.

The Mexican fighter, who is famous for handing Anthony Joshua his first professional defeat, has not fought for 11 months after he fractured his hand against Jarrell Miller in Los Angeles.

Ruiz Jnr still managed to fight his way to a majority draw - which is viewed as controversial by the boxing community - against the American last August, but had to take a considerable amount of time away from the sport to recover.

Now, 'The Destroyer' is ready to return to training and has revealed that he is 'getting ready before fight camp', while sharing a snap of some protein-filled food.

Ruiz Jnr has vowed to 'only eat protein for 3 weeks' as he diets ahead of his return, before stunning the boxing world with an update of his weight loss journey.

The once giant-killer, who is known for weighing between 255 and 275 lbs (116-125kg), shared a picture of his now trim stomach to Instagram, displaying a significant amount of weight loss.

The caption to the story, which he shared with his 1.8million followers, read: 'The diet is hard, slowly but surely. Work in progress...'

Ruiz Jnr looks remarkably different from the fighter we saw take on Miller nearly a year ago, with the Mexican weighing 274 lbs for that bout, the second heaviest he has ever been for a match.

His weight that day proved to be a real problem, as he struggled with movement around the ring and was fortunate not to lose the bout.

That was not the case when he took on Joshua in 2019. Weighing 268 lbs, the heavy underdog shocked the world by beating the Briton via TKO in the seventh round at a packed Madison Square Garden, all on just five weeks' notice.

However, when the pair fought once again in December of the very same year, Ruiz Jnr had packed on a further 15 lbs and ended up on the end of a heavy beating to lose the WBA, WBO, and IBF heavyweight titles that he had ripped away from Joshua six months earlier.

Ruiz Jnr lost comfortably via unanimous decision and has since admitted that his preparation for the second fight with Joshua was less than ideal.

'I don't want to say the three months of partying or celebrating didn't affect me, as to tell you the truth, it kind of did,' he revealed after the defeat.

'There's no excuses. The partying got the best of me. The next fight is going to be a lot different.'

It doesn't seem like he has been partying too much lately, mind. Ruiz Jnr may now be seen as a trim boxer, rather than the stocky one he was before.