Former Married at First Sight Star Jason Engler has undergone an incredible body transformation.

The 37-year-old took to Instagram on Tuesday to show off his new shredded physique.

Jason, who appeared on MAFS in 2021,  explained he took up a new health regime after someone informed him he was 'fat'.

Looking almost unrecognisable from his days on the dating show, Jason posed shirtless in one selfie and flaunted his bulked up pecs and washboard abs.

The Queenslander also posted a before photo in which he also appeared bare chested but heavier.

Jason then shared a video of himself running and explained it was the secret to his new look.

'I was informed I was fat,' Jason explained in the caption for the story.

'Looked in the mirror and what do you know a fat middle-aged man was staring back at me. 

'Starting running. Few months later still middle-aged….and greying.'

Fans and followers filled Jason's message board with words of support.

'I’ve got a block of Bega cheese that needs shredding,' joked one follower.

Another fan appeared to cast shade on Jason's new look, writing: 'Super imposed shot from the internet…But keep going I’m proud of you.'

'Propa shed bra,' messaged another. 

Fans will remember Jason matched with Alana Lister on MAFS, and while they left the season as a couple the bond ultimately did not last.

Alana later gained notoriety after becoming an Only Fans model.