Thierry Henry made his first major coup after Chelsea, and confirmed that the Monaco boss was reunited with former Arsenal Cesc Fabregas team-mate.
The Ligue 1 wrestlers made the announcement on Friday afternoon and it is the fourth round of business since the transfer window was opened on January 1, with the 31-year-old who signed a three-year contract and half after moving for a retention fee of £ 10 million.
Speaking after the agreement was confirmed, Fabregas – who took the team number 44, said: "It is a great pleasure to enter Monaco, a new project for myself.
Cesc Fabregas completed his trip from Chelsea to the Ligue 1 AS Monaco fights
The Spanish midfielder has joined the principality team with a three and a half year contract
Monaco has created a video of the player who makes a clock to announce their new signature
the midfielder announces "now, it's time" before putting a Monaco shirt on his shoulders
"The team has quality, with young players and a young coach. I'm here to help the team, I do not see the time to start, we have an important match to play this Sunday against Marseille.
"I'm really excited."
The vice president of Moanco, Vadim Vasilyev, added: "We are pleased to welcome Cesc Fabregas to Monaco, a world-class player and a great professional, whose arrival has blurred the club's ambition.
"This is clearly an excellent technical signature for the team, but we are convinced that its experience at the highest levels will bring a lot to our players in and out of the field."
In its place at Stamford Bridge, Chelsea hopes to conclude an agreement for the Nicolo Barella of Cagliari or for Leandro Paredes of Zenit St. Petersburg.
A statement issued by the Premier League club said: "Cesc Fabregas completed today a permanent transfer to Monaco.
"The passing of the midfielder to the club of Ligue 1 brings the curtain on his career for four and a half years in Chelsea, a period in which he won four major trophies, including two Premier League titles. The Spaniard made 198 appearances for Chelsea, scoring 22 goals.
"We thank Cesc for his wonderful service and wish him good luck for the next chapter of what has been a fantastic career."
Monaco has published a video with the words "Annonce Fabregas" to confirm the agreement, which depicted the Spanish with the laborious creation of a watch, before declaring: "Now is the moment".
The 31-year-old signed a three and a half year contract after leaving Stamford Bridge
Chelsea has also released a video to commemorate his time at the Bridge, in which he twice raised the Premier League, accompanied by the message: "Thanks for the memories".
Fabregas joins the new faces Lyle Foster, Naldo and Fode Ballo-Toure at the Stade Louis II while Henry fights to avoid relegation in his first season as a professional manager.
Fabregas could be launched directly into action to help his new team, who will face Marseille on Sunday evening.
The French champions of 2017 were placed second at zero, five points behind security. It will be a different challenge for the director, who has spent so much of his career on the higher end of the table.
The Spaniard left the field at Stamford Bridge in tears after his last game for the Blues – a victory in the third round of the England Cup against Nottingham Forest.
In total, Fabregas spent over a decade terrorizing the Premier League defenses
"Time flies", said Fabregas after the match. "It seems that last week started playing professionally and now it's been more than 15 years.It goes so fast and you have to be ready every three days, for criticism with everyone saying how good you are and the highs and lows.
"It seems that as it ages, it never disappears, it's technical, physicality goes away, technicality stays with you."
His start brought an incredible 12-and-a-half-year spell in the Premier League, including his time as an Arsenal player.