Eircom will announce details of its plans to buy mobile operator Meteor at its annual general meeting (agm) in Dublin today.
The €420 million purchase will be fully funded by a rights issue, details of which will also be announced to shareholders at today's meeting.
Eircom does not expect the deal to be completed before December of this year.
The Republic's biggest fixed-line provider was left in pole position to acquire the market's smallest mobile player when its only other rival, a partnership of Smart Telecom, Virgin Mobile and private investors, dropped out of the race.
Meteor's owner, US player Western Wireless, announced its intention to dispose of the Irish business last month following its merger with another US business.
The mobile operator, which has 400,000 customers, originally attracted three bids, including one from telecoms entrepreneur, Denis O'Brien. He also dropped out of the race, saying it had become too expensive.
At today's meeting, Eircom chairman, Sir Anthony O'Reilly, will seek re-election to that position for another three-year term.
Shareholders are expected to vote in favour of this.
Sir Anthony is 18 months into a three-year contract to serve as the company's non-executive chairman.
He led the Valentia Consortium take over of the company in 2001.