Southampton have signed Inter Milan midfielder Saphir Taider, with club-record signing Dani Osvaldo going the other way - both on season-long loans.
Taider, 22, who made 25 Serie A appearances last season, played against Belgium and Germany at the World Cup.
Osvaldo, 28, cost the Saints £15m a year ago but only played 13 times.
"It's part of our philosophy to bring in talented young players, and Saphir fits that bill," said Saints boss Ronald Koeman.
"I've spoken to him about the positions he can play in and he showed me real ambition. He brings competition to the squad."
Both transfers have options in place for a permanent move next summer.
"Over the course of the year, we will make a decision about the future of the player," Koeman added.
Southampton chairman Ralph Krueger also hailed Taider's arrival.
"When you get someone with such potential, a person from the World Cup, somebody already with leadership responsibility with his country, then this is something for us to be excited about," he told BBC Radio Solent.
And Krueger has promised there will be more arrivals.
He said: "We had very clear targets in mind. We are working position by position to create depth and competition from within. We have until the end of August and there will be more names."
Italian striker Osvaldo was the club's record signing in August 2013, but was sent out on loan to Juventus in January after a training-ground fight.
The former Roma forward failed to arrive back for pre-season training and was given a leave of absence.
Krueger says the exit of Rickie Lambert, Luke Shaw, Adam Lallana, Dejan Lovren and Calum Chambers is not making negotiations for new players more difficult as clubs look to take advantage of their need for replacements.
"Every negotiation is difficult but I do not think that is a factor," he said. "It's whether the player wants to leave or go that decides the price in the end."