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.
"Legally. Man to Man. No more dissing and no more talking. We in the ring with it. Challenge accepted."
The announcement comes following days of fiery exchanges between the pair via social media.
It apparently started after Soulja Boy liked and left a comment below a picture on the profile of Karrueche Tran, Chris Brown's ex-girlfriend.
The pair posted several videos and pictures mocking and threatening each other as the argument became more heated.
It wasn't long before a physical challenge was issued and that seems to have been accepted by both parties.
The three round fight is being promoted by boxing great Floyd Mayweather.
50 Cent has backed Soulja Boy for the win and says he'll be placing a $100,000 (£80,619) bet on the outcome.
Chris Brown, 27, and Soulja Boy, 26, have been criticised by fans and other celebrities for their very public feud.
Soulja Boy has even been accused of using the match as a tactic to save his flagging music career.
The exact venue and date of the fight is still yet to be confirmed but according to the flyer it will be a pay-per-view event.
Soulja Boy has already started training according to his latest Snapchat posts.
As for Chris Brown, if his dance moves are anything to go buy, he'll have the better footwork of the pair.