Stephen Kenny has replaced Mick McCarthy as Republic of Ireland manager, the Football Association of Ireland (FAI) announced on Saturday.
The former Dundalk boss was primed to take the helm once Euro 2020 came to a close, but the postponement of that tournament to next year amid the coronavirus pandemic has forced the FAI's hand.
Ireland face Slovakia in the play-offs for the continental competition, but that tie is also subject to an indefinite delay.
McCarthy, whose contract was due to expire on July 31, has therefore stepped aside early, with Under-21s boss Kenny officially taking on the role earlier than his previous start date of August 1.
"The Football Association of Ireland announces that Mick McCarthy is to be succeeded as national team manager by Stephen Kenny with immediate effect," read a statement from the governing body.
"The handover has been agreed with both men in light of the delay to the European Championship play-offs caused by the COVID-19 pandemic.
"Mick McCarthy's contract was due to expire on July 31 after the UEFA Euro 2020 finals, with Stephen initially scheduled to step up from his Under-21 team role on August 1.
"This move allows Stephen Kenny time to plan for the European Championship play-off semi-final against Slovakia later in the year."
McCarthy had taken over at the Ireland helm in November 2018, succeeding Martin O'Neill in the post for the Euro 2020 qualifying campaign after a torrid UEFA Nations League run.
The former Sunderland, Wolves and Ipswich oversaw a dramatic return to form, with Ireland winning five games and suffering defeat just once during his 10 matches in charge.
That record sealed a place in the Euro 2020 play-offs for the Boys in Green, having finished in third behind Switzerland and Denmark in their group.
It was his second spell with the nation he represented over 50 times as a player, having also been on the bench for Ireland's journey to the World Cup last-16 in 2002.