Simon Harris is set to become the youngest Taoiseach in the history of the State today.
He's due to be the only TD nominated as the Dáil votes for a replacement for Leo Varadkar.
The new Fine Gael leader will become the 16th Taoiseach of Ireland, and also the youngest at the age of 37.
Simon Harris took over as Fine Gael leader last month, after Leo Varadkar announced he's stepping down as party leader and Taoiseach.
Leo Varadkar officially handed his resignation as Taoiseach into President Michael D Higgins at Áras an Uachtaráin on Monday evening.