Writing on Instagram, Soulja Boy said: "It's going down! Signed my contract I'm leaving the fight with $1,000,000."
According to the rapper the bout will take place in March in Las Vegas and in his corner will be one of the sports all-time greats.
"I got the best ever my big bro @floydmayweather training me damn," he added.
Responding to the announcement Chris Brown told his 34 million Instagram followers it was time to stop talking.
"Now that we have your undivided attention, boxing match set," the singer wrote.