Before the mysterious dancer makes his entrance, DeGeneres reveals some early clues from the dancer, none of which are particularly helpful.
"The name starts and ends with a letter in the alphabet. I own a pair of flip flops. When I was a baby I had really short hair," DeGeneres reveals as the initial clues.
Wearing an orange suit, white shoes and gloves, and a ruffled shirt, the man who's masked by a fox head makes his entrance dancing to Jason Derulo's "Talk Dirty to Me."
During The Fox's impressive display, DeGeneres speculates that it could be Dax Shepard, but doesn't think the height matches up. tWitch, meanwhile, comments that the dancer is "not really limber, but has rhythm though."
The dance ends and the mysterious man reveals that he dances a lot, is not ticklish, counts his celeb crush as Jennifer Aniston and has "a lot of pick-up lines."
The biggest clue comes after The Fox shares that this is his third time on the show, when he says that his marital status is "a spoiler."
"So he's married," tWitch guesses.
"But that doesn't really spoil it," DeGeneres says. "There are a lot of married people."
After a couple more clues, tWitch and DeGeneres make their incorrect guesses of Ashton Kutcher and Jim Parsons respectively, before the Bachelor reveals himself.
"When he said it's a spoiler if he's married, that's why!" DeGeneres exclaims, before questioning, "So tell us now: are you married?"
"I'm happy," Underwood cryptically responds, before sharing that next week's episode will be "a good one."
Earlier this month, Underwood teased his "crazy" season of The Bachelor to ET's Leanne Aguilera.
"As the weeks progress, it gets more real and more real, and I think not only for me but these women too," he said at the time. "It's unlike anything else, and it's going to be a crazy one. You guys are in for a wild ride."
"It's going to be unexpected to a lot of people," Underwood added.
The Bachelor airs Mondays at 8 p.m. ET/PT on ABC. Join ET's Bachelor Nation Facebook group here.