The ads, which are the first work from the Post Office's new agency Mother, will form part of a multimillion-pound campaign designed to promote the role of the Post Office in the community, as well as its portfolio of services, such as foreign exchange.
The activity was overseen by Post Office marketing director Gary Hockey-Morley, who said it will form the backbone of a broader push.
'It will highlight our unique service and the broad range of competitively priced products on offer at local Post Offices,' he said.
The ads, which will break on October 14, will be set in a fictional post office. Other celebrities lined up to appear include Bill Oddie and Keith Harris and Orville.
The campaign marks a shift in strategy at the Post Office, which has recently faced negative publicity surrounding government plans to close 2500 branches by 2009 in a bid to cut its current subsidy.
The Post Office currently has a network of more than 14,000 outlets in Britain. It has been reported that managing director Alan Cook will receive a £1m bonus if he brings the planned closures in on schedule.