COMEDIAN Bill Cosby has sent a message to fans on Twitter to let them know he's still alive after rumours he was dead swept the internet.

"Bill Cosby died" was the number one trending topic on Twitter overnight, and "is Bill Cosby dead" was the number two "hot topic" on Google Trends, which tracks terms entered into the search engine.

But in the midst of the rumour's spread Cosby wrote on Twitter: "Again, I'm rebuttaling (sic) rumours about my demise."

Cosby was at the center of another death rumour in February, prompting him to tweet: "As you well know, a dead person cannot rebuttal. Therefore, I am rebuttaling to tell you that when I heard the news I immediately began rebuttaling and went into denial."

He acknowledged that "rebuttal" was not used as a verb – but said: "I don’t care, because I’m alive!"

Ever the salesman, Cosby went on to tweet overnight that he has an iPhone app available that features video and audio clips and concert information.