The fictional suburb of Carrigstown is to get its first credit union under a three-year sponsorship deal between RTÉ soap opera Fair City and the Irish League of Credit Unions (ILCU).

The sponsorship, which follows the opening of a Spar shop in Carrigstown in December 2011, is part of an ongoing campaign by ILCU to broaden the appeal of credit union membership for savers and borrowers.

The credit union is expected to be on screen from the end of April, although it is not yet clear how it will feature in the soap’s storylines.

"What we are trying to do is promote credit unions as a national brand and you can do that through a programme like Fair City . No matter what town you come from in Ireland, you have heard of Carrigstown," said Mandy Johnston, ILCU's head of communications.

Fair City is the most-watched soap on Irish television, attracting an average of 544,000 viewers an episode.

"The presence of the credit union in Fair City is a natural fit for our drama in that it reflects the values and mores of community life in Ireland," said RTÉ Television head of drama Jane Gogan. The deal fits into its plans "to make the show better and more relevant for RTÉ's audience", she added.

ILCU is understood to be paying about €240,000 over the three-year period. Unlike the Spar – which opened after regular character Christy Phelan decided to convert his corner shop to the brand – there will be no interior set for the credit union at first and only the external facade will be shown on screen.

The sponsorship follows two high-profile ILCU advertising campaigns fronted by rugby player Brian O'Driscoll and singer Imelda May, while the movement's arrival in the soap's northside community comes 56 years after the first credit union opened in Ireland.