Fraser Forster has said that he decided to move to Southampton because he wanted a "new challenge".
The Premier League side confirmed that they had signed the goalkeeper from Celtic earlier today, ending his four-year stay with the Scottish champions.
The England international told The Mirror: "I have accepted a new opportunity away from Celtic. I know the club wanted me to stay and I know they did everything they possibly can to keep me.
"It has been a brilliant experience being part of a squad which has won titles and trophies and taken part in the Champions League. But I felt now was the right time for a new challenge in the English Premier League."
The Saints are believed to have paid around £10m for Forster.
