Ryan Christie has joined Celtic from Inverness Caledonian Thistle on a four-year contract, the Parkhead club have confirmed.

The 20-year-old midfielder will return to Inverness on loan for a season, with the Scottish champions having the option of him returning to Celtic in January 2016, an option which the club are likely to exercise.

The Scotland Under-21 international has made almost 70 first-team appearances for the Highland club.

Celtic manager Ronny Deila told the club's official website: "Ryan is a hugely talented young player and it is great news that we have secured his long-term future with Celtic.

"He is someone who has so much in his game and he is a young player who will excite our fans and ultimately be an important part of our future success."

News of Christie's arrival comes after it was confirmed that Virgil van Dijk had, as widely expected, signed for Southampton.

The 24-year-old Dutch defender joined the Barclays Premier League side Southampton on a five-year deal for a fee widely reported to be around £11million.

The previous evening there was another departure from Celtic Park as striker Stefan Scepovic joined Spanish club Getafe on a season-long loan deal.

The 25-year-old Serbia international, signed from Sporting Gijon on deadline day last August, failed to find a regular start at the club, making only one substitute appearance this season.

Scepovic has made 26 appearances for the club, scoring six goals and found himself behind Leigh Griffiths and summer signing Nadir Ciftci in the pecking order at Celtic Park.

Celtic are still hoping to sign Croatian centre-back Jozo Simunovic from Dinamo Zagreb before the window closes.

The Parkhead club who have agreed a fee for Simunovic, with discussions continuing.

Defender Eoghan O'Connell was another Celtic player to sign on loan, joining Oldham until January 1, 2016, subject to international clearance.

The 20-year-old only started one game for Celtic this season, a 3-1 victory away at Dundee United.