Newcastle boss Alan Pardew has signed Swiss defender Kevin Mbabu from Servette for an undisclosed fee.
The 17-year-old agreed a three-and-a-half-year deal at St James' Park after a successful trial spell and becomes Pardew's sixth January signing.
Switzerland Under-19 international Mbabu made one first-team appearance for Swiss Super League side Servette.
"I've always wanted to sign for a club in the Premier League and Newcastle is one of the biggest there is," he said.
"I want to finish my development here with the reserves before one day training with the first team and hopefully breaking into the first team."
Newcastle reserve team manager Willie Donachie said: "Kevin is strong, confident, skilful and a very good prospect."