RTÉ has announced that the director of Lyric FM, Mr Seamus Crimmins, is to step down from his position with the Limerick-based classical music radio station.
Mr Crimmins, from Newry, Co Down, has been in charge of the station since its launch by former Arts Minister Ms de Valera in 1999.
From April, he will be joining the Arts Council on secondment, acting as arts policy director for 15 months.
The announcement comes as a surprise to many of the 30-strong staff at the station.
The arts policy director role has been created as a result of the vacancy left by Mr Dermot McLaughlin's move to Temple Bar Properties as chief executive officer.
Mr Crimmins joined RTÉ in 1981 and while on secondment will retain his RTÉ staff status.
An RTÉ spokesperson confirmed that the post of head of Lyric FM would be advertised "in due course".