Virgil van Dijk set his sights on helping Liverpool "achieve something special" after a world-record deal for the centre-back was agreed with Southampton.

The Holland international will officially move to Anfield on January 1 in a transfer that is understood to be worth £75 million, the highest price ever paid for a defender.

The deal will eclipse the £54 million spent by Manchester City to sign England full-back Kyle Walker from Tottenham during the summer and sees a protracted saga reach its end.

Van Dijk said: "Delighted and honoured to have agreed to become a Liverpool FC player. Today is a proud day for me and my family as I join one of the biggest clubs in world football."

In a message on his Twitter page, where he posed with a Liverpool shirt, he added: "I can't 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."

Van Dijk handed in a transfer request before the start of the new season, making it clear he wanted Southampton to take up the interest from Liverpool.

The Reds had issued a public apology in June for "any misunderstanding" following suggestions of an improper approach for the centre-back.

The 26-year-old trained on his own before being reintegrated into Southampton's first-team squad as he recovered from an ankle injury. He made his first appearance of the season as a late substitute in the 1-0 win at Crystal Palace on September 16.

Van Dijk, though, now has his focus firmly on helping the Reds achieve their targets over the closing months of the campaign - with Jurgen Klopp's side currently fourth in the Premier League following the 5-0 trashing of bottom club Swansea on Boxing Day.

Former Liverpool defender Jamie Carragher believes the record fee will prove money well spent if Van Dijk helps the Reds to more success.

"Rio Ferdinand went to Manchester United, for I think just over #30million, but he repaid that. He was Manchester United's top centre-back, won trophies and was there for 10 years," Carragher said on Sky Sports.

"That's what Van Dijk has to do - take Liverpool to trophies and be Liverpool's main, number one, centre-back for the next decade or so."

Meanwhile, Barcelona midfielder Paulinho says he has been in touch with Brazil team-mate Philippe Coutinho to discuss a possible transfer to the Spanish giants.

Liverpool forward Coutinho handed in a transfer request in August after La Liga leaders Barcelona had a bid for the Brazilian rejected, but the Reds turned down a further two offers, with owners Fenway Sports Group  stating he was not for sale.

The 25-year-old missed the start of the season with a back problem, but has been outstanding since his return and his stunning opener in the 5-0 St Stephen's Day demolition of Swansea was his seventh goal in as many games.

However, speculation regarding a Janaury switch to the Nou Camp for Coutinho has continued, and Paulinho - who joined the club from Chinese side Guangzhou Evergrande in August - joked that a property search for Coutinho was already under way.

"I make jokes that people are already looking for a house for him," Paulinho told mundodeportivo.com.

"I try to give him the basic information, the most important for him and his family, because maybe the time he lived here was not enough to know the city, but he knows that Barcelona is a very good city, that offers everything for him and his family.

"You have to think about the decision you are going to make. What I think is that if you have the opportunity to come, you will not regret it."