The Netherlands Under-21 international, who turns 22 in July, has signed a four-year deal with the SPL champions to become the club's second signing of the summer.
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"Celtic are delighted to announce that defender Virgil van Dijk has joined the club from FC Groningen," a club statement read.
"The Dutch Under-21 internationalist has signed a four-year deal with the Scottish champions.
"He becomes the latest player to join Neil Lennon´s squad during the close season following the arrival of striker Amido Balde from Portuguese side, Vitoria Guimaraes."
Groningen finished seventh in Eredivisie last season and qualified for the Europa league, although the player is yet to experience European football himself.