Wanheng Menayothin has reversed his decision to retire after 54 straight victories, according to the WBC.
Thailand's WBC minimumweight champion had appeared to have bowed out of the sport following a successful career which had surpassed Floyd Mayweather's unbeaten 50-fight record.
But the WBC has since confirmed that the 34-year-old intends to continue his reign as their title-holder.
The Asian Boxing Council said in a statement: "We are pleased to confirm that the current World Boxing Council minimum-weight world champion Wanheng Menayothin has not retired from professional boxing.
"The champ will look to make his next defense of his WBC world title in the coming months."
Menayothin had suggested on social media that he had been feeling the physical burden of his relentless schedule.
"I have decided that it's good to stop boxing," Menayothin wrote. "My parents, siblings have never been in boxing.
"I'm decide everything for myself. I know how I feel. No one knows my body as much as I do.
"Everyone needs money. But I would like to heal my body."
After signing a deal with Golden Boy Promotions, Menayothin had been expected to showcase his skills in America this year.
"He was set to make his US debut in April, we were excited about that but obviously it didn't happen," Golden Boy president Eric Gomez told Sky Sports.
"When you have a fighter like him with a remarkable record, it is very exciting.
"A few years back we heard of him. He has an incredible record."
News of Menayothin's U-turn has been welcomed by WBO rival Wlfredo Mendez, who has called for a unification clash.