Fernandez, of Venezuela, won last year at age 18. It was Venezuela's second straight and sixth overall win since the pageant started in 1952.
Fernandez said at a gathering of more than 20 Latina contenders that Hispanic women are always a threat to win because they work hard to prepare and look good.
Each contestant won their national competition to make Miss Universe.
The Aug. 23 pageant at the Mandalay Bay Events Center will be hosted by rocker Bret Michaels and NBC news correspondent Natalie Morales.
