Activity is set to start in the autumn and carry on through 2006, the year of the anniversary, in a bid to significantly boost funding.
Following a competitive pitch, the charity has recruited Cow as lead PR agency for the campaign. The agency will work alongside Captive Minds, which will work on entertainment-related PR.
Charity project manager Philip Treleven said details of activity are being hammered out, but are expected to include a music concert, a launch of a book celebrating 50 years of the charity, celebrity endorsement and a possible TV documentary.
The charity is seeking to increase donations by £10m from 2006 to 2011, to 'create a fitting funding legacy from the 50th anniversary celebrations', said Treleven.
'To go through the award process takes money in funding equipment, but we want to be in a position to offer all 14- to 25-year-olds the opportunity to take part. To do that we need not just volunteers, but funding as well,' he added.
The Cow team is headed by co-founder Sian Morgan, who reports to Co-operative Financial Services marketing management director David Newman, who is working as head of volunteer marketing and PR for free.
Cow, Captive Minds and advertising agency Farm have donated their time pro-bono.