The 28-year-old defender has signed from Sporting CP for an undisclosed fee. Born in Argentina, Schelotto has played for Italy at under-21 level and has also earned one full cap.
Schelotto, who says his best position is right-back but can also play on the left-hand side, had played 34 times for Portuguese side Sporting CP since joining them in 2015.
Albion manager Chris Hughton said: “We are delighted that Ezequiel is joining us. He has made nearly 190 appearances in the top flight in Italy and Portugal and has played in the Champions League, and is the type of experienced player we want to add to the squad.
“He can also play as a more attacking wing-back and so gives us some good options in defence.”
Newcastle keeper Tim Krul is set to have a medical at the training ground in Lancing tonight.