Premier League new-boys Southampton signed England U-21 defender Nathaniel Clyne from Crystal Palace on Thursday.
Clyne agreed a four-year contract but the fee Southampton will pay for the right-back is still being discussed.
The 21-year-old was out of contract at Palace, which would normally mean he was available on a free transfer, but because Clyne is under 24 the Championship team are due compensation.
If the clubs cannot settle on a figure then an independent tribunal will be used to decide how much Southampton, back in the English top-flight for the first time since 2005, will have to pay.
"I'm overwhelmed, really," Clyne told Southampton's website. "As soon as I heard that Southampton were in for me, I knew that this was the place where I could try to improve my football and get a chance to play in the Premier League."
Clyne has already joined up with his new club at their French training camp in Evian-les-Bains.
Saints manager Nigel Adkins added: "We're delighted that we can finally announce that we've brought Nathaniel Clyne into the group to help us kick onto the next level.
"For the last three years Nathaniel has been a very attack-minded full-back who bombs on, he's got pace and he's a good one-on-one defender.
"He got into the Championship team of the year last year. All being well, we can push him onto the next level now."