Chart-topping Australian-Irish performer Damien Leith will be joined by Geelong singer Imogen Brough, known to many from starring on last year's season of The Voice.

Leith, who has also been announced as the ambassador for the April 25-27 festival, shot to fame in 2006 when he won Australian Idol, beating singing sensation Jessica Mauboy in the final round.

His debut single Night of My Life reached number one on the Australian charts and was also a top 10 hit in Ireland.

His duties as festival ambassador will include presenting the award to the winner of the Australian Danny Boy Championship.

Before singing at Koroit, Brough will familiarise herself with the south-west in March when she makes her debut Port Fairy Folk Festival appearance.

Koroit Irish Festival president Chris Evans said the talent on its way to Koroit was huge news for the festival.

"To have someone of the standing and quality of Damien Leith is a coup for our festival," Evans said.

"It shows that we are able to attract some of the best performers of that Irish-Australian genre and that can only help grow our audience.

"And to also have Imogen Brough is fantastic, she will just light up the stage."