The 41-year-old was announced as the Ligue 1 side's new boss on Saturday, following the dismissal of Leonardo Jardim two days earlier.
It has been reported that the Premier League icon rejected a job offer from Bordeaux and was in advanced talks with England's Championship side Aston Villa but had a last minute change of heart and penned a deal with Monaco. "I'm incredibly excited to be given this opportunity but now the hard work must begin".
So, just how good would Henry's Monaco team have been without all their sales?
Monaco has won one game in all competitions this season.
Jardim was relieved of his duties after Monaco slipped to 18th in the Ligue 1 standings before the global break.
But the 41-year-old has made a decision to return to the club he first played at as a professional.
Henry was with Belgium on Friday as they beat Switzerland 2-1 in the Nations League.More news: Michaelle Jean defeated in Francophonie re-election bid
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Henry was more recently part of the backroom staff in Belgium's run to the semi-finals of the World Cup, where they finished third ahead of England.
Thierry Henry became a key player for Arsenal under manager Arsene Wenger (right). He scored 175 goals in two different spells for Arsenal and is now the Gunners' record goalscorer in the Premier League.
Henry was a World Cup victor with France in 1998 and won the European Championship two years later, scoring 51 goals in 123 appearances for Les Bleus.
"Thierry is both aware of the task ahead and eager to start his new job".
Monaco chief executive officer Vadim Vasilyev, said Henry could "count on our trust and all our support to bring a new dynamic to the team and carry out the mission".
Ampadu has left his role with Arsenal's youth team to join Henry in Ligue 1, with Benfica's U23s coach Joao Carlos Calado Trahlo also joining the former Gunner.