Australia's Megan Anderson faces the biggest challenge in her booming career when she battles dual UFC champion Amanda Nunes in Las Vegas.
Up for grabs on Saturday (Sunday AEDT) is Nunes' featherweight belt.
Nunes, who has reigned at bantamweight since 2016 and featherweight since 2018, is one of only four fighters to hold two belts simultaneously - the others being Conor McGregor, Daniel Cormier and Henry Cejudo.
Her 11-fight winning streak over the past 6 1/2 years is the longest by a woman in UFC history, yet her last two opponents took her to decisions - although Nunes lost just one round combined in those two fights.
This is, however, the Brazilian's first fight in nine months and her first since her wife - fellow UFC fighter Nina Ansaroff - gave birth to their first child.
Anderson, who served two and a half years in the Australian military, goes into the bout with a 11-4 record.
After consecutive wins over Zarah Fairn Dos Santos (round one submission) and Norma Dumont Vian (first-round knockout), Anderson earned a showdown with Nunes.
Their fight was first scheduled for December 12 but was postponed after the champion withdrew due to an undisclosed injury.
The six-foot Anderson does enjoy a significant reach advantage over Nunes, who is a good four inches shorter than the challenger.
Though Nunes is the overwhelming favourite Anderson refuses to be intimidated.
"I'm just ready to put on a show," Anderson said. "Everyone is invincible until they're not."
Their bout is one of three title fights on the UFC259 card.
The main event is a champion vs champion superfight, as undefeated middleweight king Israel Adesanya (20-0) of New Zealand goes up in weight and challenges newly crowned light heavyweight titleholder Jan Blachowicz (27-8) of Poland.
Also on the card is an intriguing bantamweight title fight as Russia's Petr Yan (15-1) makes his first defence of his belt against American Aljamain Sterling (19-3).
Yan brings a 10-fight win streak, which includes four finishes in his seven UFC fights, into the bout. Sterling has won five in a row and seven of eight.
Australian Associated Press