CONOR Mcgregor has brutally rejected Floyd Mayweather's offer to help him prepare for his UFC comeback against Khabib Nurmagomedov.
Mayweather, who beat the Irishman in a boxing match 12 months ago, invited his old rival to work out at his gym in Las Vegas ahead of the October bout.
But his olive branch was snapped in half when McGregor tweeted: "F*** the Mayweathers, except Senior and Roger.
"There is no peace here kid.
"Step up or step down."
McGregor, 30, may have been goading Mayweather, 41, into a UFC rematch after urging the 50-0 boxing legend to try his hand at MMA earlier this year.
The American replied with a picture of himself punching McGregor, captioned: "Easiest 9 figures I ever made! All work is what?"
McGregor was stripped of the lightweight title in April because he hadn’t fought in the UFC since he won the belt against Eddie Alvarez in November 2016 at UFC 205.
Former UFC lightweight king McGregor takes on reigning champ Khabib on October 6 at UFC 229 in a bid to win it back.
Mayweather has admitted he doesn't know much about the Russian, but is backing McGregor at least to give it his all.
He said: "I don't really have a prediction because I've never seen the guy fight that's facing Conor McGregor, from what I know he's a hell of a guy that's on the ground, hell of a grappler – and he can wrestle.
"But the fans want to see you stand up and fight.
"Conor McGregor, he's a tough competitor. He's not gonna back down from anyone, he's not scared, he's a warrior."