Chelsea have swooped to snap up Atletico Madrid midfielder Saul Niquez on a season-long loan.
The deadline day deal includes an option for the Blues to buy the 26-year-old next summer.
After making 447 appearances and scoring 53 goals for Atleti, Saul decided the time was right to leave the reigning LaLiga champions.
Despite interest from Manchester United and the switch seemingly falling through earlier in the window, the European champions made a late move to bolster Thomas Tuchel's squad with the Spanish international.
Saul said: "I am very excited to start this new challenge with Chelsea.
"Blues fans, I am one of you now and I can’t wait to wear the shirt, start training and see all of you.
"See you soon!"
Chelsea director Marina Granovskaia added: "We welcome Saul to the club and believe he completes our squad as we compete for honours this season.
"He is a proven winner, a player with huge experience and we know he will be very well suited to the challenges that face us on all fronts."
Tuchel had been keen to add another central midfielder before the window slammed shut and Saul will provide competition for Jorginho, Mateo Kovacic and N'Golo Kante.
Meanwhile, Ethan Ampadu has joined Serie A side Venezia on loan after extending his deal at Stamford Bridge.
The versatile Welshman, 20, is now tied to the Blues until 2024.