West Ham signed Italy defender Emerson Palmieri from Chelsea in a deal worth a reported £15 million ($17 million) on Tuesday.
Emerson has agreed a four-year contract with the Hammers, with the option of a further one-year extension.
The 28-year-old left-back was born in Brazil, but moved to Italy in 2014 and was eventually granted citizenship.
He struggled to break into the Chelsea team in five years at Stamford Bridge and spent last season on loan at Lyon.
Emerson has won 27 caps for Italy and played in their win over England in the Euro 2020 final at Wembley.
"I'm very happy to be here and to arrive here. It's a big challenge for me, it's a big team, so I'm very happy to be here and I'm ready," Emerson told West Ham's website.