Neil Lennon will take charge of Celtic until the end of the season after Brendan Rodgers agreed to take charge of Leicester, Press Association Sport understands.
The Parkhead club "very reluctantly" granted Rodgers permission to hold discussions with the Premier League outfit, who are looking for a successor to Claude Puel following his dismissal on Sunday.
And the Scottish champions moved quickly to install a replacement by lining up Lennon for a return to the job he left in 2014.
Lennon's appointment is expected to be confirmed later on Tuesday and he will attend a press conference at Celtic Park on Wednesday morning ahead of the Ladbrokes Premiership game against Hearts at Tynecastle later that evening.
Lennon won three league titles and two Scottish Cups in just over four years as Celtic manager after taking over from Tony Mowbray, initially on a temporary basis, in March 2010.
Rodgers' departure has proven to be a swift farewell after Celtic confirmed Leicester's approach early on Tuesday.
A Celtic statement read: "Celtic Football Club today confirmed that it has been approached by Leicester City FC to speak to Brendan Rodgers with regards to their current managerial vacancy.
"Brendan has indicated to the club that this is an opportunity he wishes to investigate further and therefore, very reluctantly, the club has granted him permission to speak to Leicester City."
The former Liverpool boss has been in charge at Parkhead since 2016 and led Celtic to an unprecedented domestic double-treble with the Hoops on course for a third.
Celtic are eight points clear of Rangers with the Betfred Cup already in the trophy room and with a William Hill Scottish Cup quarter-final against Hibernian, whom Lennon left in January, to come at Easter Road on Saturday.
However, it is understood the former Swansea boss has always wanted to return to the Premier League at some stage.
He now has the chance to take over the club which pulled off a stunning title triumph in 2016.
Puel was sacked the day after Saturday's 4-1 home defeat to Crystal Palace.
The loss saw Leicester slip to 12th in the table and left them still looking for their first win of 2019 following a miserable run which also saw them knocked out of the FA Cup at League Two Newport.
If appointed, Rodgers will become Leicester's third permanent manager since they sacked title-winning boss Claudio Ranieri in February 2017.
Former Celtic striker Chris Sutton criticised Rodgers over the timing of his expected departure.
Sutton told BT Sport's Twitter account: "The timing of it stinks. He's going to a club who are playing for absolutely nothing – they are not going to get relegated, they are not going to get into Europe – and I am really disappointed.
"I think there are a lot of Celtic fans out there as well who will feel let down.
"This is the job which Brendan said was his dream job. So why is he going now to a club who have nothing to play for?"
