The Europe-wide ad campaign will be created by T-Mobile ad agency Saatchi & Saatchi with MediaCom handling all media planning and buying.
The deal will see T-Mobile use new technology such as concert live-streaming and full track downloads to bring customers closer to Robbie Williams' music.
Williams, who has won a record 15 Brit awards, said: "The future is music by mobile -- T-Mobile is making it happen today."
In addition, T-Mobile customers will be able to download Williams ringtones, wallpaper and logos and will get the chance to win VIP tickets to his concerts, backstage passes and after-show parties.
Phil Chapman, UK marketing director for T-Mobile, said the deal will play a significant part in encouraging young people to download music through their mobile handsets.
"Partnering with a global star such as Robbie Williams while creating a unique experience for his fans truly demonstrates our commitment to strengthening the relationship between music and mobile technology," Chapman said.
"Our goal is to make mobile music accessible, exclusive and enjoyable, which is why partnering with the biggest artist in Europe is a great fit."
A household name in Europe with hits such as 'Angels', 'Millennium' and 'Rock DJ', Williams has sold more than 51m albums worldwide.
The partnership will also incorporate mobile devices from Sony Ericsson, which will be embedded in handsets for maximum exposure.
Williams joins 'Oceans Twelve' actress Catherine Zeta Jones and tennis stars Andre Agassi and wife Steffi Graf as past celebrities to endorse T-Mobile.
If you have an opinion on this or any other issue raised on Brand Republic, join the debate in the Forum.