Liverpool formally unveil former Celtic defender Virgil van Dijk

The 26-year-old's switch from the Saints was agreed last week, but with the January transfer window now open his deal, understood to be worth £75million - the highest fee ever paid for a defender, is now sealed.

Celtic will receive over £6 million due to a sell-on clause as part of the deal when the defender was sold to Southampton for £12 million in 2015.

The Dutchman told Liverpool's official website: "With the history at the club and everything around it - even the training ground and stuff - it is just a perfect, perfect match for me, and for my family as well."

The transfer fee eclipses the £54m spent by Manchester City to sign England full-back Kyle Walker from Tottenham last summer.

"Obviously there is a lot of money being paid, but I can't do anything about that money, I can't do anything about the price - nobody can," the Holland international added.

"It's only the market. The only thing I can do is just work hard, do the good things and be 100 per cent every day. That's what I definitely want to do - and I am going to do.

"I am happy to be here and I can't wait to get started. I think the most important thing is the size of the club, the culture of the club, the players, the manager and obviously the fans, who make the club this special.

"I think this is the right time for me to be here and to develop all sorts of aspects of my game. I am looking forward to doing that, that's the main thing."