Sharon Osbourne marked her comeback by posing with two shirtless men wearing kilts at the Hilton Glasgow Grosvenor Hotel.
Returning X Factor judges Gary Barlow, Nicole Scherzinger and Louis Walsh greeted fans as they arrived for the first stages of the competition.
The show, now in its tenth series, is being overhauled this year with the introduction of Double Auditions.
Contestants will initially have to perform for the judges in an intimate audition room, like in earlier seasons of the show.
If the acts pass the first audition, they will then be required to sing at an arena to prove they have what it takes for Boot Camp and the Live Shows.
The X Factor, which returns to ITV this autumn, will also hold auditions in Birmingham, Manchester, London and Cardiff.