The two clubs have agreed an undisclosed fee for the 27-year-old. Halford still had two years left to run on his Portsmouth contract, but the League One club have been desperately trying to shift players off the books in order to stave off the threat of liquidation. His arrival at the City Ground follows on from Forest's capture of Welsh defender Danny Collins and Halford feels the time is right to make the move. "It's been a tough year but the administrator wanted us all out," Halford told Forest's official website. "Not knowing whether there was going to be a club was very unsettling. "It had to come to an end eventually. This is the right time for me to be here. The facilities are great. I know the owners have got big plans to develop here as well. "I never really heard of any solid interest until three or four days ago. I had a quick chat with the manager which went well and things progressed very quickly "I can't wait to get started." Halford becomes the third player to be sold by Portsmouth this week after Luke Varney and David Norris both signed for Leeds United.