Hornicek has agreed a five-year deal after the Magpies activated his 30-million-euro (£25.7 million, $34.6 million) release clause, and he becomes the club's fifth signing of the summer.

"The last few days have been an emotional rollercoaster from when I first heard about the move and now I'm so happy to be here," said the 24-year-old, who is expected to supplant Nick Pope as first-choice goalkeeper.

"I know Newcastle is a huge football city, with 52,000 fans at St James' Park creating an incredible atmosphere and pushing the team every game. I can't wait to play in front of them."

Newcastle sporting director Ross Wilson said Hornicek had "firmly established himself as one of Europe's top young goalkeepers".

Eddie Howe left his position as Newcastle boss last week after five years at the club.

The Magpies struggled to a 12th-place finish in the Premier League last season and have endured a difficult summer transfer window.

Italy midfielder Sandro Tonali has moved to Tottenham and England forward Anthony Gordon has departed for Barcelona, while captain Bruno Guimaraes has been strongly linked with a move to Premier League champions Arsenal.

Newcastle start their Premier League campaign at home to Liverpool on August 23.