Fabregas, 31, made his final appearance for Chelsea in the 2-0 FA Cup win over Nottingham Forest on Saturday, and Monaco have now confirmed his arrival on the French Riviera, per the club's official Twitter account:
The Spaniard was largely consigned to the Blues bench following the arrival of manager Maurizio Sarri, who preferred £50 million summer-signing Jorginho. The Italy international followed his former Napoli boss to Stamford Bridge and became a key part of the first XI.
The move to Ligue 1 sees Fabregas link back up with former Arsenal team-mate Thierry Henry, who took over at the helm of the French club in mid-October. Monaco are in a fight to avoid relegation to Ligue 2, although Henry has improved the side somewhat since then to win three of their last eight games in all competitions—they also beat Rennes on penalties in the Coupe de la Ligue quarter-final.
Fabregas leaves England for a second time and has made a combined 504 appearances for Chelsea (198) and Arsenal (306). He will now hope to recapture some of his former first-team impact at Monaco.
Only one of his six Premier League appearances under Sarri was as part of the starting XI.
However, former Chelsea team-mate Eden Hazard paid huge praise to the playmaker after Fabregas captained the team to victory over Forest on Saturday, via HaytersTV:
The midfielder teared up after he was substituted off late on in that win, which came on the same day Sky Sports reported Henry was close to securing the signing of his old Emirates Stadium comrade.
Fabregas reflected on his life in football and gave the impression he was about to close a significant chapter in his career when he spoke after Saturday's win, per Chelsea's official website:
"It feels like it was last week I started playing professionally, and now it is over 15 years.
"It is a long time, but for the young players when they start playing, my little advice is to enjoy it every single second because it goes so fast. In football you have to be ready every three days, you have to live with criticism, you have to live with everyone saying how good you are—up and downs—and you just think I am young, I have time, but time really does fly, so enjoy every single second of it."
This will be Fabregas' first venture outside the Premier League or La Liga, where he represented boyhood club Barcelona between 2011 and 2014.
Monaco are 19th in Ligue 1 and four points adrift of safety reaching the halfway point in their season, and if utilised correctly, Fabregas could become a vital tool in helping the team pull off an escape before May.