Premier League side Southampton have announced the long-awaited signing of Celtic’s Dutch centre-back Virgil van Dijk.

The defender has put pen to paper on a five year deal for a fee which is expected to rise to around £12 million.

Celtic will be line to benefit from any further sale of the 24-year-old, as it is understood that they have agreed a 20 per cent sell on clause in case the former-Groningen man moves on from St Mary’s in the future.

Ronald Koeman was made to wait to sign his compatriot, who has three caps for the Netherlands' under-21 side, as Celtic were keen to keep the 24-year-old in their attempts to qualify for the Champions League. However, the Scottish champions failed to do this, falling to a 4-3 defeat on aggregate to Swedish giants Malmö FF in their final play-off, and thus the Dutch manager now has his man.

Van Dijk happy with the move

Upon his arrival on the South Coast of England, the former Groningen defender told Southampton's official website that he was "delighted" to have made the move, revealing that "it was a very easy decision to join [the] club."

Van Dijk dubbed the Saints as "a very ambitious club," one "who have been doing very well in last couple of years," which convinced the player that this move is "the right step" for him to take in his career.

Southampton bolstering squad whilst Celtic pursue replacement

The defender will act as a direct replacement for Toby Alderweireld, who impressed on loan from Atletico Madrid last season, but signed for Tottenham Hotspur this summer.

As well as losing the Belgian this window, Southampton have also lost right-back Nathaniel Clyne and midfielder Morgan Schneiderlin, who have completed big moves to Liverpool and Manchester United respectively.

However, van Dijk becomes Koeman's seventh signing of the window, and the 10th player to arrive at the Saints with Eredivisie experience. Striker Graziano Pellè described his new teammate as "head and shoulders above" defenders in the Dutch top flight whilst he was at Feyenoord, competing against van Dijk who was playing for Groningen.

Celtic, on the other hand, are set to announce his replacement, Dinamo Zagreb’s Jozo Simunovic, later today.