She will oversee the design of both athlete kit and fan wear for the Olympic and Paralympic Games.
“As a British fashion designer it is an amazing, once-in-a-lifetime opportunity,” she said.
Cyclist Victoria Pendleton added: “I’m a massive Stella fan. With London being host it’s really important as the host nation to set the standards.”
Full sport: BBC Sport – Stella McCartney to design 2012 Team GB Olympic outfits