Liverpool has signed central defenders Mamadou Sakho and Tiago Ilori for a combined fee of about £25m.
Sakho, 23, who has 14 France caps, will cost around £18m from Paris St-Germain.
Sporting Lisbon's Ilori, 20, has represented Portugal at youth level but is still eligible to play for England because he is born in London.
Sakho told the club's website: "I came here because the project at Liverpool interests me. I'm really looking forward to playing my first game."
He is manager Brendan Rodgers' most expensive signing of the summer and can play in the centre of defence as well as at left-back.
Liverpool managing director Ian Ayre said: "He's an important marquee signing for us. It was a difficult one to do and it was a difficult one for us to get, but I'm very pleased that we've been able to attract him to the football club."
Ilori, who cost £7m, said: "Liverpool has a great team and I think it's the place for me to be at the moment.
"There have been some great teams here in the past and the club has won a lot of trophies and I want to be a part of it."
Rodgers has now signed seven players this summer following the captures of Kolo Toure, Iago Aspas, Luis Alberto, Simon Mignolet and Aly Cissokho.
Liverpool prioritized defensive recruitments because Sebastian Coates has been ruled out for most of the season while Toure and Cissokho are also injured.
Sakho and Ilori were both at Anfield on Sunday to watch Liverpool beat Manchester United to move top of the Premier League.