Michael Conlan claimed TJ Doheny had "lost your b****" as the pair clashed during Tuesday's press conference.
They are set to trade leather in a huge all-Irish showdown at Falls Park on Friday to open up this year's Feile an Phobail.
Around 8,000 fans will provide a cauldron atmosphere at the West Belfast venue, as Conlan looks to claim another victory which will earn him a world title shot later this year.
Tuesday's press conference had been respectful until Doheny raised issues over the weight limit for Friday's fight.
It has emerged that Conlan and Doheny will clash at a 124lbs catchweight, two pounds higher than the super-bantamweight limit which the fight was originally set for.
It has also been announced that the interim WBA featherweight world title will be on the line.
Doheny claimed Conlan "hadn't been the most professional" and questioned whether his opponent could make 122lbs.
"The fight had been agreed upon before I flew to the US for my training camp. It was to be 10 rounds at Falls Park at 122lbs," Doheny started, before Conlan fired back: "TJ, stop bottling it. Stop bottling it. You're bottling it, TJ.
"The fight's happening. What are you going to do? Walk away? You're bottling it, you're losing your b****."
The fiery exchange continued when Doheny replied: "Don't be getting upset because you can't make the weight.
"You say you're going to outbox me, well that's all you can do because you can't crack an egg."
(Fast forward the Facebook Live video to 19:13 to hear the exchange...)
