Portsmouth have signed Glen Johnson from Chelsea on a four-year deal for a fee believed to be about £4m.
Johnson made his England debut in 2003
The 23-year-old right-back, who joined Chelsea from West Ham for £6m in July 2003, spent last season on loan at the Fratton Park club.
"Portsmouth is a fantastic club with a lot of nice people," said Johnson.
"The fact that I played here last season was a big factor in my decision. Manager Harry Redknapp was a massive factor, too. He has belief in me."
He added: "The team is doing well again last season. I saw them play at Chelsea last
week and they were definitely unlucky not to get a point.
"The thing is I just want to play as many games as I can here now.
"There has been great progress made and that has been shown by having two players in the next England squad and Sol Campbell and David James obviously deserve their success."
He was Chelsea's first signing of the Roman Abramovich era but soon found himself moved down the pecking order behind Paulo Ferreira and Geremi.
Johnson has five England caps, having made his debut in 2003 against Denmark.
Chelsea assistant manager Steve Clarke added: "It just hasn't worked out for Glen here and at this stage of his career he needs to play.
"If he can do that I'm sure he will still go on to fulfil his potential."