The campaign starts this week and is the first brand campaign created for the telecoms company by Adam & Eve. The Jack character has been used for the past five years and was created by the previous incumbent WCRS.
The new campaign will push the value proposition of the mobile phone retailer in response to the recession.
Phones4U is traditionally a heavy television advertiser but the latest campaign is expected to take a more integrated approach and also include outdoor and online.
This will be the first big campaign overseen by Phones4U marketing director Russell Braterman. He was appointed to the role late last year and took over from Jim Slater who left the company.
Braterman oversaw the appointment of Adam & Eve in January to handle its |£7m advertising account following a three-way pitch against Mother and incumbent WCRS
A Phones4U spokeswoman says it will reveal details of the campaign tomorrow (June 9).