Side-by-side pic: Conor McGregor 'before' and 'after' going up to 170 pounds from being 145-pound champion

Ultimate Fighting Championship (UFC) Featherweight champion Conor McGregor stepped on the scale at the UFC 196 weigh-ins today 25 pounds heavier than usual, set to make his welterweight debut and prove to the world weight classes are irrelevant.

He certainly isn't the first mixed martial arts (MMA) fighter to jump up or down two weight classes (indeed, B.J. Penn fought from featherweight to a 226-pound Lyoto Machida in an openweight bout) but he's certainly the first UFC champion to do so.

The "Notorious" McGregor landed at 170 pounds, making official his welterweight showdown in the main event against Nate Diaz tomorrow (Sat., March 5, 2016) at the MGM Grand Garden Arena in Las Vegas, Nevada.

Daaaayum. "Steaks for breakfast. Steaks for lunch. Steaks for brunch. Grass-fed, massaged. Beef. All day long." Indeed.

Regardless of physical appearances, this fight isn't the one McGregor originally wanted when he left Frankie Edgar standing at the featherweight altar to go up to 155 pounds and fight Rafael dos Anjos in the quest to become the first simultaneous two-division UFC champion.

But dos Anjos dropped out of the fight with less than two weeks to go, citing a broken foot (and not a vagina), leaving McGregor without a dancing partner. Dropping back down to 145 pounds was also off the table as Frankie Edgar called in sick as well.

After some speculation about who would step in and replace dos Anjos, the UFC called area code 209 and found one Nathan Diaz willing to step up and throw down with a man who has wrecked all comers in the promotion since he debuted in 2013.

Although Diaz is an underdog in this fight he's certainly a live dog for any opponent, putting together a 13-8 record in UFC since his 2007 debut. Despite admitting he might "get murked" he's never back down from a game of mental warfare as evidenced by his staredown with McGregor yesterday (see how quickly it got out of control here).

For complete UFC Fight Night 82 weigh-in results click here.