Development agency Cafod ran a multimedia campaign aimed at Catholics in the north west of England last week, asking people to donate the cost of a meal to help the world's poor.
Liverpudlian actor Joe McGann and TV and film writer Jimmy McGovern gave their support for the launch of Cafod's 'Give up a Butty for Fast Day' appeal.
McGann recorded a radio advert for the appeal, which was aired on local stations.
The campaign is running with door-to-door, press and street activity - local schoolchildren carried a giant 'butty' through the streets in Liverpool and Chester, which both have large Catholic populations.
McGovern, who wrote hit ITV series Cracker, said: "I wish I was steadfast enough to say I'll give up beer. But I fear I'm not. However, I do promise to go without lunch that day."
Some of the money will go to aid flood victims in Bangladesh.