Robbie Neilson has returned to Hearts as manager in place of Daniel Stendel after leaving Dundee United.
Neilson, 40, has signed a three-year deal after compensation was agreed with the Tannadice oufit.
He said he was “delighted” and that you “don’t turn down the chance” to return to a club of Hearts’ stature.
United rejected an initial approach on Sunday but, after Neilson made clear his desire to leave, a compensation deal was struck.
The former Scotland international said he was “keen to pick up where I left off”, having left Hearts second in the league when he departed for MK Dons in December 2016.
“Everyone knows there is a really good squad and I’m excited to begin working with the players,” added Neilson, who thanked United for giving him an opportunity.
“I hope the United fans feel that together we managed to restore the club back to where it belongs.”
Stendel’s contract ended when the Tynecastle club were relegated but he had not officially left the role.
But he has now been replaced by former player and head coach Neilson, who led United to the Scottish Championship title last term, having done the same with Hearts in 2015.
United are due to replace Hearts in the top flight when the season starts on 1 August, but the latter are legally challenging their relegation.
The Edinburgh outfit, along with Partick Thistle, filed a petition at the Court of Session on Wednesday to demand that all promotions – included United’s – are scrapped.
And now they have taken the Tannadice club’s head coach, a week after they began pre-season preparations for their first top-flight campaign since 2016.
Neilson’s assistants – Gordon Forest and Lee McCulloch – will take charge in the interim, with United keen to appoint a new head coach “as soon as possible”.
United chairman Mark Ogren said they were “understandably disappointed” but that the club is “bigger than one person” and they they “look towards the future, with a new leader and renewed hope”.
Former Barnsley boss Stendel was appointed in November after Craig Levein was sacked and won five of his 17 matches in charge and secured a place in the Scottish Cup semi-finals.
However, Hearts were bottom of Premiership when the season was ended and face demotion.
Former Hearts and United defender Neilson started his management career at Tynecastle as head coach in 2014, shortly after the club had been relegated and come out of administration.
Working under then director of football Levein, Neilson won 62 of his 106 games in charge and follow up that Championship title win with a third-placed finish in the top flight.
Hearts were second the following season when he left for a 13-month spell in charge of MK Dons, before joining United in 2018.
His first campaign ended in Premiership play-off final defeat at the hands of St Mirren, but United were 14 points clear with eight games to play when this season was curtailed.