It is the first time in history a fashion mogul has been recruited to design for an Olympic Games.
'I started out with some crazy ideas; neon fish; metallic gold; fluorescent, for God's sake,' the 40-year-old told Grazia magazine.
It took McCartney two years to put together the complete Stella McCartney for Adidas range, but when it was finally launched at the Tower of London last week a number of commentators slammed the designs.
Many were outraged at the decision to feature a blue Union flag on the kit and some branded the range a 'massive fail' for not featuring the national colours.
One Facebook user said: 'Massive fail!!!! These are not our national colours!!!! Did someone not get the memo.'
While another wrote: 'Oh dear! Stella, Stella - did you not think of asking ANYONE on a UK street if they thought it was reasonable for you to take the red off our Union Jack?'
However McCartney, who was promoted to Adidas Team GB Creative Director.two years ago, took to Twitter to defend her creations.
She wrote: 'I see many feel as strongly about the Union flag as I do! The design actually uses more red & shows more flag than any Team GB kit since '84.'
Jessica Ennis models the new Olympics 2012 uniform, designed by Stella McCartney for Adidas
The colour aside, a greater concern to McCartney was the individual need of the athletes.
With different body shapes, competing in different sports she had a range of possibilities to consider.
'There are eight different bodies for each sport, each with their own set of rules and they all have a say.
'Of course you can't do parallel bar work with a suit full of sparkles,' she added.
During the design process McCartney spent lots of time with the athletes and trainers talking to them about their requirements.
Some revealed that they felt their appearance impacted their athletic performance while others didn't care what they looked like, as long as their clothing would help shave seconds off their time.
But for all continuity was important, and all wanted to feel part of a team. She said: 'Ultimately, we wanted the athletes to feel like a team and be proud with the identity we created.'
Athlete Phillips Idowu who helped parade the new outfits at the launch said: 'All eyes will be watching London 2012 so every little detail matters.
'I love what Stella has done with the design.
'Looking good is psychologically important but my sprint suit is also technically advanced, so not only do I look good but I also have confidence in the technology in the kit.'
The sportswear combines the best in performance technologies and stand-out British style, according to Adidas who brought McCartney on board as creative director.
The flag is broken down and appears in different ways on the kit.
Up to 175,000 items of clothing will be supplied to British athletes competing in 26 Olympic and 20 Paralympic sports at London 2012.
The Olympic volunteers' uniform - a loose tracksuit top and pink poloshirt - were not well received
VIDEO: Watch the Stella McCartney official Olympics kit launch catwalk show
