Atsu, who spent the 2016-17 campaign on loan with the Magpies - playing 32 times - has signed a four-year deal
The transfer, announced by Newcastle on Wednesday, is subject to the Ghana international successfully reapplying for a work permit
"We are happy to sign a good player," Manager Rafa Benitez told the club's official website.
"He's shown us that he's a good professional and someone who is very keen to learn and improve
"Christian has been a key part of our promotion campaign and he wants to help us to build something for the future.:
Atsu took time to settle into life in the Championship, but made a significant impact towards the end of the season as Newcastle staged a late fightback to snatch the title from Brighton's grasp.
He scored in the 4-1 victory over Preston which secured promotion and again in a 2-0 win at Cardiff four days later which set the stage for a dramatic final day.
Source : PA
Source: PA