50 Cent ''wouldn't have a bad day'' if his estranged son Marquise Jackson was to be ''hit by a bus''.

The 43-year-old rap star - who has Marquise, 21, with his ex-girlfriend Shaniqua Tompkins - made the comment on an Instagram photo of Marquise posing alongside his long-time rival Kenneth 'Supreme' McGriff.

50 - whose real name is Curtis Jackson - responded to the image by typing: ''If both these little n****** got hit by a bus, I wouldn't have a bad day (sic)''

50's original comment prompted a backlash from people on social media, and the chart-topping rap star subsequently took to his Twitter account to defend himself.

50 - who also has a six-year-old son called Sire with Daphne Joy - wrote on the micro-blogging platform: ''I have zero ill will towards anyone living on this Earth. The people Shanquois son looks up to and associates with is a reflection of the negative energy he embraces towards me. I paid his mother $1,360,000 in support to afford him opportunities I never had. (sic)''

Marquise previously spoke out about his strained relationship with 50, accusing the rapper of not being ''around enough'' during his younger years.

He said: ''It completely went south when I was probably like ten or 11. He wasn't really around enough.''

And according to Marquise, their relationship has deteriorated even further since that time.

Marquise admitted: ''He's still alive but I can't tell you our last conversation or the last time we even had a dialogue.''

Marquise's mother famously sued 50 for $50 million amid claims they'd agreed he would take care of her financially for life. However, Shaniqua's case was dismissed in 2009.