Crystal Palace have signed Benfica defender Jose Fonte on loan for a year, with a view to a permanent move.
The 23-year-old's younger brother Rui is a reserve-team striker for Arsenal.
Palace boss Peter Taylor said: "I am quite excited about this one because he is a young player, as well as a good centre-back and a good footballer.
"There were other clubs in for him, but his brother plays for Arsenal and he wants to come to London, so we have been quite fortunate there."
Fonte said: "I am very happy to be here. I want to show my value and what I am capable of."
The central defender spent last season on loan at Portuguese side Estrela Amadora.