Macpherson and her new judging lineup - Julien Macdonald, Whitney Port and Tyson Beckford - are looking to find a superstar model, who will win a contract with international agency Models 1, a cover and feature within Company magazine, a contract with Revlon cosmetics, a luxury holiday to The Atlantis Palm in Dubai, an apartment at the trendy 51 Buckingham Gate and an international campaign with high street store Miss Selfridge.
The 20 girls include 18-year-old Amelia Raven, party animal Anita Kaushik, "zany" Anna Vokes, punk rocker Anne Winterburn, Cardiff's Catherine Corry, tomboy gap year student Danielle Steven and actress Diona Doherty.
Miss Great Britain finalist Emma Grattidge, Newcastle student and karate black belt Emma Sharratt, 19-year-old tattoo enthusiast Jennifer Joint, 21-year-old Kelly Forde, Oxshott student Letitia Herod, 18-year-old Lisa Madden and cross-country runner Louisa Warwick are also taking part.
Completing the lineup are business student Madeleine Taga, call centre worker Penelope Williamson, Congo-born Rissikat Oyebade, mum-of-one Roxanne O'Connor, Victoria's Secret wannabe Tasmin Golding and Essex mum Vanessa Cox.
International supermodels Andrej Pejic, Paul Sculfor, Erin O'Connor and Tali Lennox, and style icon Poppy Delevigne will help the judges pick out a star, while Alesha Dixon, Melanie B and Kimberley Wyatt are among the celebrities guesting on the show and casting a critical eye over the contestants.
Britain & Ireland's Next Top Model starts on Monday, July 9 at 9pm on Sky Living.