Liverpool on Thursday announced the signing of Brighton's World Cup-winning Argentina international Alexis Mac Allister for a reported fee of £55 million ($69 million).
The midfielder, 24, is the first piece in a midfield rebuild for Liverpool, who finished a disappointing fifth in the Premier League.
"It feels amazing," said Mac Allister. "It's a dream come true. It's amazing to be here and I can't wait to get started.
"I wanted to be in from the first day of pre-season, so it's good that everything is done. I'm looking forward to meeting my teammates.
"It was a fantastic year for me -- World Cup, what we achieved with Brighton -- but now it's time to think about Liverpool and try to be a better player and a better human being every day."
Liverpool manager Jurgen Klopp is seeking more new signings after the departures of midfielders James Milner, Naby Keita and Alex Oxlade-Chamberlain.
The club were priced out of a move for England teenage star Jude Bellingham, who is set to join Real Madrid after the clubs agreed a fee of 100 million euros ($107 million).