The 26-year-old, is a new addition to the panel along with male model Tyson Beckford.
The American newcomers replace two British judges from season six, stylist Grace Woodward and male model Charley Speed.
The appointments may come as a surprise to many industry insiders who had widely predicted E! Fashion Police panel member Kelly Osbourne to be the newest judge.
For Miss Port, who worked as a model, on staff at Teen Vogue and later as a PR before launching her own fashion label, Whitney Eve, the new role marks something of a career high.
She said in a statement: 'I am so excited to be joining Britain & Ireland's Next Top Model. I'm a huge fan of the show and am honoured to be in the company of the talented fellow judges and host, all fashion figures and designers I admire.
'As a designer and someone who loves fashion, this is a role I’m really looking forward to. Plus any chance to spend more time in the UK is an added bonus.'
The hires are a major coup for Ms Macpherson, too, who is executive producer of the show.
Explaining her choices, she revealed: 'It was incredibly important for us when considering who we should hire, that the individuals chosen brought with them personal experience and success which would perfectly complement the show's aspirations and style.
'In Whitney and Tyson, I know we have come up trumps.'
Britain & Ireland’s Next Top Model will air on Sky Living this summer.
credit - dailymail.co.uk
~Kelli at Hills Freak
~Kelli at Hills Freak