Adidas becomes the official sportswear partner for the games and also will provide clothing for the 70,000 volunteers and officials.

The deal also covers sponsorship for clothing and equipment used by British athletes for the 2008 Beijing Games, the 2010 Vancouver Winter Games and 2012 London Games.

"No other host city has made such progress in its domestic sponsorship five years out from the games," London 2012 chairman Sebastian Coe said.

Adidas flew in world champions Tyson Gay and Allyson Felix for today's launch, and the pair ran on a mock racing track on the Millennium Bridge over the River Thames to highlight the deal.

The sponsorship announcement also featured Nadia Comeneci, who won a combined five gold medals in gymnastics at the 1976 and 1980 Olympics. England soccer star David Beckham also made an appearance via a hologram — speaking about his joy at competing in front of crowds in his native London.

Adidas joins British bank Lloyds TSB, which has signed up as a banking and insurance partner, and EDF Energy, which has the utilities sponsorship. London hopes to name a fourth sponsor by Christmas.

"Our objective, and I think we'll probably get there, is to have all our tier one sponsors in place by Beijing, which would be the first time a host city has done that," Coe said.

The other categories are telecoms, automotive, airline, oil and gas and a clothing and homeware manufacturer.

The top-tier sponsors will help raise 2 billion pounds (US$4 billion; euro2.9 billion) for the London Olympic organizing committee.