Newcastle have signed Jamal Lewis from Norwich City on a five-year contract for £15m, rising to £20m with add-ons.
Northern Ireland full-back Lewis, 22, is the fifth player to move to St James' Park in this transfer window.
He follows winger Ryan Fraser and forward Callum Wilson from Bournemouth, midfielder Jeff Hendrick from Burnley and Mark Gillespie, who arrived from Motherwell.
"Jamal is a very exciting prospect," said Magpies manager Steve Bruce.
"I watched him flourish in the Championship two years ago and he made a real fist of it in the Premier League last season."
Lewis, who came through the academy at Norwich and made his first-team debut in December 2017, said Newcastle's move for him was a "little bit unexpected".
"It was something that I was obviously looking forward to when I heard that there was serious interest, so I'm delighted to be here now - Newcastle's such a great club with such history," he added.
Lewis was named in the Professional Footballers' Association Championship Team of the Year in 2019 after playing a key part in Norwich's promotion to the Premier League.
He made 28 top-flight appearances as the Canaries were relegated last season.
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