Other big names that took to the stage included Liam Gallagher, Janet Jackson, Kylie Minogue, Miley Cyrus and George Ezra.
His album 'Wasteland Baby' reached the top of the Billboard 200 charts in the US earlier this year.
The Bray native will join The Strokes, Florence & The Machine, and The 1975 in headlining this year's Electric Picnic.
More than 57,000 tickets for the country's biggest music festival sold out in record time last December.
Christine and the Queens, Dermot Kennedy and Billie Eilish will also perform at the festival in Laois this September.
While touring the States as part of his Wasteland Baby tour, her made a suprise appearence at a New York Subway station.
Dropped in on some New Yorkers’ commute home tonight for a quick subway session. #wastelandbaby 🎧 hozier.lnkk.to/wastelandbabyPosted by Hozier on Wednesday, March 6, 2019
He also made an appearence on The Late Show With Stephen Colbert on CBS