Portsmouth have signed defender Martin Cranie on a three-year deal from local rivals Southampton.
Cranie, 20, was out of contract at Southampton and had refused the offer of a new deal to stay at the club.
Pompey will have to pay a compensation fee to Championship side Saints as the player is under the age of 23.
Cranie told BBC Radio Solent: "I didn't really think about the rivalry between the two clubs, I just wanted to come down here at play football."
He added: "I'm very happy to be back in the Premiership. I've been down in the Championship for a couple of seasons now, but to get back to the top flight, it's a pretty big step for my career.
"Harry Redknapp was the manager who gave me my chance in the Premiership when he was at Southampton, so he was a big part in my decision to move here."