West Ham United manager David Moyes says Emerson Palmieri will bring experience and pedigree to his squad.
The Italy left-back completed a move from Chelsea on Tuesday.
"We are very pleased to welcome Emerson to West Ham United," said Moyes.
"He is an experienced player with a good pedigree, who has enjoyed great success at both club and international level in recent years.
"He will give us strong competition in defensive areas and brings a winning mentality that we are looking to build here at West Ham. We look forward to working with Emerson and wish him all the very best in his career with us."