World heavyweight boxing champion Tyson Fury announced his retirement via social media before claiming he had changed his initial decision only hours later on Twitter.

Fury, 28, dethroned the legendary Wladimir Klitschko as the WBA, WBO and IBF world champion last year in one of the biggest shocks ever seen in the heavyweight division.

A rematch had been scheduled and then postponed twice, first due to injury and then to "health issues" reported by Fury's camp recently.

"Hahahaha u think you will get rid of the GYPSYKING that easy!!!," tweeted Fury.

"I'm here to stay. #TheGreatest just shows u what the Medea (sic) are like.

Fury had said earlier on Monday: "I'm the greatest, and also retired."

But he claimed three hours later he was only joking.

"Soon as I get better I'll be defending what's mine - the heavyweight throne," he said.

And after appearing to have hung up his gloves, he seems to have reversed his initial decision.

A few days ago ESPN alleged that the boxer had tested positive for cocaine earlier in September.

Fury responded by posting a Photoshopped picture of himself as Tony Montana, the character played unforgettably by Al Pacino in 'Scarface'.