Chelsea have announced the departure of Conor Gallagher to Spanish side Atletico Madrid.
The midfielder signed a five-year contract with Atleti.
Gallager, a boyhood supporter of the former English giant made 90 appearances for his side scoring 10 goals. He joined at the age of 10.
He had entered the final year of his contract at Stamford Bridge so Chelsea wanted to sell now to avoid losing him on a free transfer next summer.
"To everyone at Chelsea, thank you for making my dreams come true," Gallagher wrote on Instagram. "It's been an absolute honour every time I put on the shirt, and it was a dream come true to captain the team on many occasions.
"I loved every moment. These memories will last forever. I appreciate all the love and support from the fans."
Meanwhile Atletico forward Joao Felix has arrived at Chelsea reportedly agreeing to a £40 million ($51 million) fee.
Felix had a disappointing six-month loan spell at Stamford Bridge in the second half of the 2022-23 season, scoring four goals in 20 appearances.