Rapper 50 Cent has launched a scathing attack on boxer Billy Dib, labelling the Australian “ungrateful” and claiming TV network HBO deemed him “unwatchable”.

Dib was one of 50 Cent’s first clients when he launched a boxing promotions company in July 2012, however their relationship turned sour when the business went bankrupt and the Australian claimed he was owed more than $1 million.

• Cricketers could soon be seeing red under new trial
• Corrupt tennis umpires banned, reveals ITF

In the lead-up to his return to fighting later this month, the former IBF world champion labelled the venture with the rapper his “worst career move”, prompting 50 Cent to hit back via Instagram.

“The truth is Billy Dib is an ungrateful fighter who was deemed unwatchable by premium networks like Showtime and HBO when I met him,” 50 Cent wrote.

“With a record of 35-1 (21 KOs), Dib must have fought 21 cab drivers in Australia because Evgeny Gradovich with a record of 15-0 (8 KOs) beat the s*** out of him, despite taking the fight on a month’s notice.”

The stinging rant also included claims that world champion Floyd Mayweather was mad with 50 Cent when he opted to sign Dib, and referred to the Australian’s lack of fight time in the USA.

The truth is Billy Dib is an ungrateful fighter who was deemed unwatchable by premium networks like Showtime and HBO when I met him. Floyd was mad at me for signing him in the first place. With a record of 35-1 (21 KOs), Dib must have fought 21 cab drivers in Australia because Evgeny Gradovich with a record of 15-0 (8 KOs) beat the shit out of him, despite taking the fight on a month’s notice. It’s no secret that the level of competition and talent, fighting in America is the highest. The best fighters in the world come here to fight. 8 Months later, I put Dib on the Manny Pacquiao undercard for the rematch with Gradovich. He got knocked the fuck out. I can only set the fight up…I can’t fight for you, punk! I didn’t take a dime of your money. They call me a lot of shit, but never a thief. #EFFENVODKA #FRIGO #SMSAUDIO ANOTHER 💩 SHIT HEAD

A photo posted by 50 Cent (@50cent) on Feb 10, 2016 at 9:31am PST

“It’s no secret that the level of competition and talent, fighting in America is the highest. The best fighters in the world come here to fight,” he said.

“8 Months later, I put Dib on the Manny Pacquiao undercard for the rematch with Gradovich. He got knocked the f**k out.

“I can only set the fight up … I can’t fight for you, punk! I didn’t take a dime of your money. They call me a lot of s**t, but never a thief.”

Dib, whose wife Sara died from cancer last September, will make his return to the ring against Thailand’s Sukkasem Kietyongyuth in a super featherweight bout on February 26 at Sydney’s Emporium Function Centre.