Chelsea have signed goalkeeper Djordje Petrovic from New England Revolution for £12.5m plus £1.5m in add-ons.
The 23-year-old Serbia international will compete with Robert Sanchez for the number one spot at Stamford Bridge.
It comes after Kepa Arrizabalaga left the club to join Real Madrid on loan while Edouard Mendy signed for Al-Ahli.
Petrovic said: "It's a big step and it's always been a dream of mine to sign for one of the biggest clubs in the world."
He added: "Today I have achieved that goal and I'm so happy."
Petrovic played 43 times in MLS for New England and has two caps for Serbia.