Leicester City have reached an agreement with Freiburg to sign Turkey defender Caglar Soyuncu in a deal reported to be worth up to £19m.
Earlier on Thursday, the Foxes signed Croatia Under-21 defender Filip Benkovic, 21, from Croatian side Dinamo Zagreb for a reported £13m fee.
"I will give all my heart to this club, the fans, to everybody," Benkovic said.
Soyuncu, 22, has agreed a five-year contract and the transfer is subject to a work permit being granted.
He played 30 times for Freiburg as his side finished 15th in the Bundesliga last season.
The deals came on the same day striker Jamie Vardy signed a new four-year deal with the club.
Soyuncu made his senior debut for his national side aged 19 against Sweden in March 2016 and has since been capped a further 14 times.
Meanwhile, Benkovic has agreed a five-year deal at the King Power Stadium.
"The ambitions of Leicester City are so big," he said. "I think it's a very good step for me to go to the next level. I'm very happy to be here."
The Foxes have already signed right-back Ricardo Pereira, centre-back Jonny Evans, midfielder James Maddison, goalkeeper Danny Ward and winger Rachid Ghezzal.
Benkovic adds further depth to manager Claude Puel's squad before their Premier League opener at Manchester United on Friday (20:00 BST).
Puel said: "Filip is an exciting young player who has the potential to develop even more at Leicester.
"He has made a big contribution to Dinamo Zagreb over the last three years and has also benefitted from experiencing European football.
"I know he will give us some great options and competition in the squad and I'm delighted to have him here."