Brondby defender Daniel Agger has signed for European champions Liverpool in a four-and-a-half year deal.
"The parties have agreed not to disclose the details of the transfer deal except from the fact that Liverpool will play against Brondby in a friendly at Brondby Stadium," the Danish club said in a statement.
Agger, 21, is Benitez's second major signing of the transfer window after Dutch defender Jan Kromkamp's arrival from Villarreal last week.
"Daniel is a player we have been following for a long time," Benitez told Liverpool's website.
"We've been told he's one of the best centre halves in Denmark for 20 years. A lot of scouts have spoken highly of him and there has been lots of interest from other clubs."