Canelo Alvarez and Daniel Jacobs decided not to wait until Saturday night before squaring off in a face-to-face showdown.
During Friday's weigh-in, Alvarez and Jacobs were involved in a skirmish on the stage at the T-Mobile Arena in Las Vegas:
The lead-up to the altercation saw the two boxers pushing their heads together and Jacobs appearing to say something that caused Alvarez to shove him.
It would appear Jacobs is following the Conor McGregor blueprint of promoting a fight by leaving the audience with a memorable final moment leading up to the big event.
Now is when things get difficult for Jacobs. The 32-year-old will attempt to win the lineal middleweight title and defend his IBF middleweight crown against an opponent whose only loss in 54 fights was against Floyd Mayweather Jr.