James DeGale has branded George Groves a "fake" and a "puppet" ahead of their grudge match on May 21.
The pair meet at the O2 Arena, London, in a British and Commonwealth super-middleweight title dust up.
And their war of words shows no sign of letting up, with DeGale letting rip in an interview with the Independent on Sunday.
"Groves is a fake," said DeGale.
"He thinks he's David Haye but he's just a puppet. Adam Booth [Groves's manager] has his hand right up his backside, talking for him, telling him what to say and what to do.
"At least with me, what you see is what you get. I just tell you the way it is. People may say I'm disrespectful and rude, me calling him the ugly kid and all that, but the truth is we don't like each other.
"It's serious. Obviously some people don't like me either, they say I'm arrogant and that I think I'm it, but if at the end of the sentence they say, 'Well, he's a good fighter', then I'm happy with that."
"Yeah, it's personal all right, I can't stand him and it's mutual. It goes back 10 years. Basically he's been living in my shadow.
"He beat me in the national championships but two years later it was me they chose for the Olympics. We both boxed for the same amateur club and since I won that gold medal he's always been bitter and a bit jealous."