For the last few months, UFC welterweight champion Kamaru Usman has been trying to chase down a crossover boxing match with four division world champion Saul "Canelo" Alvarez.

Usman believes the fight will be bigger than the 2017 showdown between UFC superstar Conor McGregor and five division champion Floyd Mayweather.

In that matchup, Mayweather broke down and stopped McGregor in the tenth round.

The event it was a massive financial success. Mayweather-McGregor became the second biggest moneymaker in pay-per-view history.

UFC President Dana White believes Usman would make a very big mistake if he stepped in the ring with Canelo.

Usman, due to his contractual obligations, would need White's blessing in order to face any opponent outside of the UFC.

And White is far from being on board with allowing Usman to face Canelo in a boxing match.

He feels Usman-Canelo is not on the same level - in terms of public demand - when compared to the Mayweather-McGregor encounter.

"He (Usman) is serious about it, he shouldn't be serious about it," White said to Sky Sports. "I don't like that fight at all.

"Everything about it is horrible. It's a stupid fight to make, it makes no sense. I don't know how many people would be interested in seeing that.

"When Conor and Floyd fought it took on a life of its own. Everywhere I went people asked me if those two are going to fight. It just kept building, building and building. It ended up being the biggest pay-per-view ever. Something could come along but the whole Boxing vs MMA thing is silly."

Usman has been out of the cage since November, when he picked up a decision win over division rival Colby Covington. 

Canelo, who also saw action last November when he knocked out Caleb Plant, will face WBA light heavyweight champion Dmitry Bivol on May 7.