The three-year contract will kick-off with advertising appearances rolled out across the network of Motorola stores and distributors throughout Asia.
Motorola will also have rights to exclusive Beckham content such as screensavers and videoclips of the England and Real Madrid footballer in action on the mobile operator's handsets.
Beckham will start the role immediately and will be seen carrying Motorola products throughout the World Cup.
In addition, the 31-year-old star will be supporting Motorola initiatives including the newly launched RED mobile phone created to help eliminate Aids in Africa.
Part of the proceeds from the sale of these phones and consumers' monthly mobile bills will go to the RED fund, which was set up by U2 singer Bono and is also backed by Gap and American Express, to raise money for Aids in Africa.
Jeremy Dale, vice-president of retail marketing at Motorola Mobile Devices, said: "We look forward to working with him [Beckham] across a range of projects.
"In particular, that he'll be using his immense popularity to help promote Moto Red."
Mother has been appointed to handle the advertising for the Red campaign.
In July last year, Beckham was dropped as the public face of mobile network Vodafone.
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