The 46-year-old designer has been handed the responsibility of ensuring that Justin looks at his best for the biggest performance of his career on Sunday (04.02.18), when he'll perform in front of a huge global audience as the New England Patriots take on the Philadelphia Eagles.
Stella and Justin, 37, have worked together on an outfit that's been inspired by his soon-to-be-released 'Man of the Woods' album, according to Women's Wear Daily.
The outfit will consist of an organic cotton shirt that features landscape artwork by Martin Ridley.
The McCartney-designed outfit also boasts a single-breasted jacket and matching trousers made in Prince of Wales check.
In December, meanwhile, Stella encouraged budding designers to be ''honest'' with themselves.
The British star - who launched her namesake brand, which is entirely cruelty free, in 2001 - advised people looking to break into the fashion industry to be ''passionate'' and true to themselves when they are launching a label or a collection.
She said: ''Find what drives you, what you are passionate about, and be honest with yourself.''
And the creative mastermind said that when an entrepreneur is ''lucky enough'' to crack the business, they must try to be unique about their work and stand out from the crowd.
She explained: ''If you are lucky enough to break into the industry, try and enjoy it, but also try and do something different. I think the world is looking for a point of difference. There aren't enough people in fashion approaching it in a different way.''
His new album Underneath It All is out now.