The Republic of Ireland's foreign minister has been nominated as the tánaiste (deputy prime minister) after a police whistleblower scandal forced Frances Fitzgerald to resign.
Simon Coveney, who will remain foreign minister, stood against Leo Varadkar in the race to become PM in June.
The father-of-three is a central figure in the country's Brexit negotiations.
Had she not stood down, a vote of no confidence in her could have led a snap Irish election.
This would have complicated next month's EU meeting, at which the Republic of Ireland's position will influence the assessment of the UK's progress in Brexit talks.
Ms Fitzgerald served as tánaiste before also taking on the role of minister for business, enterprise and innovation.
Taoiseach (Irish prime minister) Leo Varadkar said he had accepted her resignation with "deep regret".
Ms Fitzgerald quit hours before a motion of no confidence in her was to be proposed by the main opposition party, Fianna Fáil.
Mr Varadkar has also appointed Heather Humphreys as her successor as Minister for Business, Enterprise and Innovation and Josepha Madigan as culture minister.
Ms Humphreys was previously the Minister for Arts, Heritage, Regional, Rural and Gaeltacht Affairs.Ms Madigan is a TD (member of parliament) for Dublin Rathdown having been elected for the first time at the 2016 General Election.
The new appointees will make their way to Áras an Uachtaráin (the president's residence) to collect their seals of office.
Delighted to appoint @simoncoveney as Tanaiste. This will enhance his position across Europe in our vital Brexit negotiations.— Leo Varadkar (@campaignforleo) November 30, 2017
Mr Coveney, 45, was educated at the exclusive Clongowes Wood boarding school in County Kildare, which has produced a number of high-profile Irish politicians and writers.
However, as a teenager, the Cork native was expelled from the school for drinking alcohol and bunking off lessons to attend a beach party.
In a candid interview with Irish national broadcaster RTÉ, he revealed he had suffered from a stutter when he was younger, and lived in the shadow of his more promising brother, who is now a successful businessman.
He went on to study management at the Royal Agricultural College in Gloucestershire, England, before his election as the youngest member of the Dáil in 1998, in a by-election caused by the death of his father.
Mr Coveney remained in the Dáil until 2004, when he was elected to the European Parliament.
Very proud and humbling day for me. To be appointed Tanaiste and Dept PM of Ireland is an enormous responsibility - I will do everything in my power to serve everyone in our country with integrity and positivity - thank you for the privilege.... pic.twitter.com/a48d29xFf4— Simon Coveney (@simoncoveney) November 30, 2017
Returning to the Dáil in 2007, he was appointed agriculture minister in 2011 and responsibility for defence was added to his portfolio three years later.
He had made no secret of his desire to lead the Fine Gael party and in contrast to Mr Varadkar, he was seen as the more centre-left candidate in the recent leadership contest.
When RTÉ asked the question about his intentions some years ago, he said: "I am very ambitious, so the straight answer is yes, some day."