Logan Paul and KSI officially went full Mayweather vs. McGregor today in L.A. ... and the bros' brouhaha to promote their upcoming bout got a little physical on stage.
The YouTube superstars took nonstop shots at each other -- mostly verbal -- at a massive news conference outside the L.A. Coliseum at noon Saturday. Their younger brothers, Jake Paul and Deji, opened up the presser ... because they're the undercard for the mega boxing event at Manchester Arena on August 25.
Heavyweight boxer Shannon Briggs was the surprise emcee, as the Pauls flaunted fancy suits and traded insults with KSI and Deji ... who opted for more casual wear.
The most exciting moment came when KSI put on a Logan Paul wig, which Logan yanked off and followed with a push ... which prompted KSI to charge like a bull. Unfortunately ... no punches were thrown.