He was a £500,000 purchase from Coventry City last month and joins new summer arrivals Romain Amalfitano and Curtis Good.
All three are raw talents but are seen as having massive potential to become first-team stars of the future.
Alan Pardew: “Bigi has done really well. He has impressed us. He has come in from Coventry with a season of first-team football under his belt at 18. He is exactly the type of player we should be bringing to Newcastle United.
“And he will get better here – 100%. Oh, and he gets Bigi as a nickname being as he’s 5ft 4in!
“He has looked really fine in training with guys who are at a higher level than he’s been used to. Bigi has looked really good and that’s great credit to him.”