Not many fighters can claim to have been reigning UFC champions in two different weight divisions. Then again, not many fighters ever were granted such an opportunity.
Those opportunities have been more frequent since 2016. Here is a look at the fighters so far in UFC history who can call themselves a "double champ" or "champ champ" and say they were UFC champions in two weight classes at the same time.
McGregor first won the featherweight title by knocking out Jose Aldo in 13 seconds at UFC 194 in December 2015. Eleven months later, he sat atop the octagon in Madison Square Garden holding up both the featherweight and lightweight titles after he stopped Eddie Alvarez in the second round at UFC 205. He never defended either title and eventually was stripped of both.
Cormier became the light heavyweight champion when he submitted Anthony Johnson in the third round to claim the vacant title at UFC 187 in May 2015. Cormier defended the belt twice, lost it to Jon Jones in July 2017, then got it back a month later when that bout was overturned to a no-contest after Jones tested positive for a performance-enhancing substance. In July 2018, as the reigning light heavyweight champion, Cormier knocked out heavyweight champion Stipe Miocic in the first round at UFC 226 to become the double champ. Cormier vacated the light heavyweight title shortly before he was to be stripped of the belt when Jones and Alexander Gustafsson fought the belt at UFC 232 on Dec. 29, 2018.
Nunes took the women's bantamweight title from Miesha Tate with a first-round submission at UFC 200 in July 2016. In the next 22 months, Nunes defended that title by beating Ronda Rousey, Valentina Shevchenko and Raquel Pennington. At UFC 232 in December 2018, Nunes moved up to challenge featherweight champion Cris Cyborg, who hadn't lost an MMA fight in 13 years. Nunes knocked her out in 51 seconds to claim both belts.