Liverpool will sign Virgil van Dijk when the transfer window re-opens in January after agreeing a world-record deal to sign the Southampton defender.

The Dutch centre-back will move to Anfield in a transfer that is understood to be worth £75m, eclipsing the previous world-record fee for a defensive player set when Manchester City bought Kyle Walker for £53m.

Liverpool announced on Wednesday night: “Liverpool Football Club can confirm they have reached an agreement with Southampton for the transfer of Virgil van Dijk.

13 Premier League transfers that could happen in January Show all 13 1 /13 13 Premier League transfers that could happen in January 13 Premier League transfers that could happen in January Philippe Coutinho – Liverpool to Barcelona Liverpool's Brazilian midfielder Philippe Coutinho takes a free kick that is saved during the English Premier League football match between Liverpool and Everton at Anfield in Liverpool, north west England on December 10, 2017. / AFP PHOTO / Paul ELLIS / RESTRICTED TO EDITORIAL USE. No use with unauthorized audio, video, data, fixture lists, club/league logos or 'live' services. Online in-match use limited to 75 images, no video emulation. No use in betting, games or single club/league/player publications. / (Photo credit should read PAUL ELLIS/AFP/Getty Images) AFP/Getty Images 13 Premier League transfers that could happen in January Mesut Ozil – Arsenal to Manchester United SOUTHAMPTON, ENGLAND - DECEMBER 10: Mesut Ozil of Arsenal during the Premier League match between Southampton and Arsenal at St Mary's Stadium on December 10, 2017 in Southampton, England. (Photo by Catherine Ivill/Getty Images) Getty Images 13 Premier League transfers that could happen in January Danny Rose – Tottenham to Manchester United LONDON, ENGLAND - DECEMBER 06: Danny Rose of Tottenham during the UEFA Champions League group H match between Tottenham Hotspur and APOEL Nikosia at Wembley Stadium on December 6, 2017 in London, United Kingdom. (Photo by Tottenham Hotspur FC/Tottenham Hotspur FC via Getty Images) *** Local Caption *** Danny Rose Tottenham Hotspur FC via Getty I 13 Premier League transfers that could happen in January Thomas Lemar – Monaco to Chelsea or Arsenal Monaco's French midfielder Thomas Lemar runs with the ball during the French L1 football match between Bordeaux and Monaco on October 28, 2017 at the Matmut Atlantique stadium in Bordeaux, southwestern France. / AFP PHOTO / NICOLAS TUCAT (Photo credit should read NICOLAS TUCAT/AFP/Getty Images) AFP/Getty Images 13 Premier League transfers that could happen in January Alex Sandro – Juventus to Chelsea or Manchester United TURIN, ITALY - OCTOBER 25: Alex Sandro of Juventus in action during the Serie A match between Juventus and Spal on October 25, 2017 in Turin, Italy. (Photo by Tullio M. Puglia/Getty Images) Getty Images 13 Premier League transfers that could happen in January Jack Wilshere – Arsenal to West Ham United SOUTHAMPTON, ENGLAND - DECEMBER 10: Jack Wilshere of Arsenal during the Premier League match between Southampton and Arsenal at St Mary's Stadium on December 10, 2017 in Southampton, England. (Photo by Catherine Ivill/Getty Images) Getty Images 13 Premier League transfers that could happen in January Ross Barkley – Everton to Chelsea LIVERPOOL, ENGLAND - MAY 12: Ross Barkley of Everton shows appreciation to the fans as he is subbed off during the Premier League match between Everton and Watford at Goodison Park on May 12, 2017 in Liverpool, England. (Photo by Alex Livesey/Getty Images) Getty Images 13 Premier League transfers that could happen in January Andy Carroll – West Ham United to Everton LONDON, ENGLAND - NOVEMBER 24: Andy Carroll of West Ham United warms up prior to the Premier League match between West Ham United and Leicester City at London Stadium on November 24, 2017 in London, England. (Photo by Julian Finney/Getty Images) Getty Images 13 Premier League transfers that could happen in January Jonny Evans – West Bromwich Albion to Manchester City WEST BROMWICH, ENGLAND - NOVEMBER 28: Jonny Evans of West Bromwich Albion during the Premier League match between West Bromwich Albion and Newcastle United at The Hawthorns on November 28, 2017 in West Bromwich, England. (Photo by Michael Steele/Getty Images) Getty Images 13 Premier League transfers that could happen in January Olivier Giroud – Arsenal to Everton Arsenal's French striker Olivier Giroud celebrates scoring the team's first goal during the English Premier League football match between Southampton and Arsenal at St Mary's Stadium in Southampton, southern England on December 10, 2017. / AFP PHOTO / Adrian DENNIS / RESTRICTED TO EDITORIAL USE. No use with unauthorized audio, video, data, fixture lists, club/league logos or 'live' services. Online in-match use limited to 75 images, no video emulation. No use in betting, games or single club/league/player publications. / (Photo credit should read ADRIAN DENNIS/AFP/Getty Images) AFP/Getty Images 13 Premier League transfers that could happen in January Danny Ings – Liverpool to West Bromwich Albion T)LIVERPOOL, ENGLAND - DECEMBER 11: (THE SUN OUT. THE SUN ON SUNDAY OUT) Danny Ings with Emre Can of Liverpool during a training session at Melwood Training Ground on December 11, 2017 in Liverpool, England. (Photo by John Powell/Liverpool FC via Getty Images) Liverpool FC via Getty Images 13 Premier League transfers that could happen in January Daniel Sturridge – Liverpool to West Ham or Crystal Palace LIVERPOOL, ENGLAND - NOVEMBER 27: (THE SUN OUT, THE SUN ON SUNDAY OUT) Daniel Sturridge of Liverpool during a training session at Melwood Training Ground on November 27, 2017 in Liverpool, England. (Photo by Andrew Powell/Liverpool FC via Getty Images) Liverpool FC via Getty Images 13 Premier League transfers that could happen in January Virgil van Dijk – Southampton to Liverpool Southampton's Dutch defender Virgil van Dijk warms up ahead of the English Premier League football match between Liverpool and Southampton at Anfield in Liverpool, north west England on November 18, 2017. / AFP PHOTO / Paul ELLIS / RESTRICTED TO EDITORIAL USE. No use with unauthorized audio, video, data, fixture lists, club/league logos or 'live' services. Online in-match use limited to 75 images, no video emulation. No use in betting, games or single club/league/player publications. / (Photo credit should read PAUL ELLIS/AFP/Getty Images) AFP/Getty Images

“The Reds have agreed a deal with the south coast club, and the player himself, that will see the 26-year-old defender move to Anfield when the transfer window re-opens on January 1, 2018.”

Van Dijk, who will be assigned the squad number four, commented that he was “delighted and honoured” to join the Merseyside club, who currently sit fourth in the Premier League table.

Writing on his Instagram page, Van Dijk said: “Today is a proud day for me and my family as I join one of the biggest clubs in world football.

“I cannot wait to pull on the famous red shirt for the first time in front of the Kop and will give everything I have to try and help this great club achieve something special in the years to come.”

Personal terms of around £180,000-a-week have been agreed between Van Dijk and the club. Both Manchester City and Chelsea were also interested and had made inquiries with Southampton at different stages over the past six months, but the defender has long had his heart set on a move to Anfield.

Klopp has been determined to improve his side's defence (Getty)

The agreement completes months of protracted negotiations between the two clubs, with Van Dijk first handing in a transfer request in August. “I have been left frustrated by the club's position that I am not for sale and am disappointed that enquiries from multiple top clubs have been consistently rebuffed,” he complained at the time.

However a move fell through when Liverpool apologised for making an alleged illegal approach for the 26-year-old, after Southampton made an official complaint to the Premier League.

Van Dijk remained on the south coast but missed the start of the season amid concerns over his focus and mentality, before being slowly reintegrated back into the first-team under new manager Mauricio Pellegrino.

Van Dijk will become the world's most expensive defender (Getty)

However he has made just 12 appearances in all competitions this season and was left out of recent games against Chelsea, Huddersfield Town and Tottenham Hotspur.

Van Dijk is now the most expensive defender in world football and the second most expensive transfer in Premier League history.

His fee of £75m is level with Manchester United striker Romelu Lukaku and behind only the club’s £90m purchase of Paul Pogba, in August 2016.