| Person | Type | Job | Role(s) | Episodes |
|---|---|---|---|---|
 Jonathan Bullen | Crew | Directing | Director | 1 |
 Simon Cowell | Crew | Creator | Creator | |
 Ayda Field | Cast | Actress | Self - Judge | 28 |
 Barry Manilow | Cast | Actor | Self - Special Guest | 2 |
 Beyoncé | Cast | Actress | Self | 2 |
 Brian Friedman | Cast | Actor | Self - Creative Director | 5 |
 Britney Spears | Cast | Actress | Self - Special Guest | 1 |
 Céline Dion | Cast | Actress | Self - Special Guest | 2 |
 Dannii Minogue | Cast | Actress | Self - Judge | 118 |
 Dermot O'Leary | Cast | Actor | Self - Presenter | 312 |
 Gary Barlow | Cast | Actor | Self - Judge | 94 |
 Gloria Estefan | Cast | Actress | Self - Performer | 1 |
 Jason Donovan | Cast | Actor | Self - Special Guest | 1 |
 Julio Iglesias | Cast | Actor | Self - Special Guest | 1 |
 Kate Thornton | Cast | Actress | Self - Presenter | 83 |
 Kelly Rowland | Cast | Actress | Self - Judge | 31 |
 Kylie Minogue | Cast | Actress | Self - Special Guest | 2 |
 Lionel Richie | Cast | Actor | Self - Special Guest | 2 |
 Mariah Carey | Cast | Actress | Self - Special Guest | 2 |
 Michael Bublé | Cast | Actor | Self - Special Guest | 3 |
 Michelle Thorne | Cast | Actress | Self | 2 |
 Myleene Klass | Cast | Actress | Self - OB Presenter | 3 |
 Nicole Scherzinger | Cast | Actress | Self - Judge | 123 |
Ray Quinn | Cast | Actor | Self - Contestant | 1 |
 Robbie Williams | Cast | Actor | Self - Judge | 28 |
 Rod Stewart | Cast | Actor | Self - Special Guest | 2 |
 Ronan Keating | Cast | Actor | Self - Guest Judge | 1 |
 Sharon Osbourne | Cast | Actress | Self - Judge | 203 |
 Tony Bennett | Cast | Actor | Self - Special Guest | 2 |
 Usher | Cast | Actor | Self - Special Guest | 1 |
Andy Abraham | Cast | Self | 1 | |
 Caroline Flack | Cast | Actress | Self - Presenter | 28 |
 Chico Slimani | Cast | Self | 1 | |
 Jeff Brazier | Cast | Self - OB Presenter | 5 | |
 Louis Walsh | Cast | Actor | Self - Judge | 367 |
 Rita Ora | Cast | Actress | Self - Judge | 28 |
Simon Cowell | Cast | Actor | Self - Judge | 329 |
 Will Young | Cast | Actor | Self - Special Guest | 2 |
 Katy Perry | Cast | Actress | Self - Special Guest | 1 |
Leon Jackson | Cast | Self - Auditionee | 1 | |
 Nick Grimshaw | Cast | Actor | Self - Judge | 28 |
Niki Evans | Cast | Self - Contestant | 3 | |
 Harry Styles | Cast | Actor | Self - Contestant | 3 |
 Liam Payne | Cast | Actor | Self - Contestant | 2 |
 Louis Tomlinson | Cast | Actor | Self - Judge | 28 |
 Niall Horan | Cast | Actor | Self - Contestant | 1 |
 Olly Murs | Cast | Actor | Self - Presenter | 28 |
 Zayn Malik | Cast | Actor | Self - Contestant | 2 |
 Leona Lewis | Cast | Actress | Self - Special Guest | 2 |
 Katherine Jenkins | Cast | Actress | Self - Special Guest | 1 |
Michael Underwood | Cast | Self - OB Presenter | 3 | |
 Alexandra Burke | Cast | Actress | Self | 5 |
 Luke Johnson | Cast | Actor | Self - Dancer | 3 |
 Shayne Ward | Cast | Self | 1 | |
 Kian Egan | Cast | Actor | Self - Judges' Expert | 1 |
 Mary Byrne | Cast | Actress | Self - Contestant | 1 |
 Brenda Edwards | Cast | Actress | Self | 1 |
Brendan Murray | Cast | Actor | Self - Contestant | 8 |
 Dalton Harris | Cast | Actor | Self - Contestant | 10 |
Carl Pemberton | Cast | Self | 1 | |
Sharon Conway | Cast | Self | 1 | |
Sinead Conway | Cast | Self | 1 | |
Nicholas Dorsett | Cast | Self | 1 | |
Marie Conway | Cast | Self | 1 | |
Laura Conway | Cast | Self | 1 | |
Andy Pemberton | Cast | Self | 1 | |
Maria Lawson | Cast | Self | 1 | |
Phillip Magee | Cast | Self | 1 | |
Chenai Zinyuku | Cast | Self | 1 | |
| Person | Type | Job | Role(s) | Episodes |
