Hudson aims to join Gabor Gyepes in the Bluebirds' central defence
Cardiff City have signed centre-back Mark Hudson, 27, from Charlton in what the Addicks say is a £1m-plus deal.
Hudson said: "Whenever I have played here [at Cardiff] the supporters have always been superb for the home team."
Charlton boss Phil Parkinson said: "We wish Mark all the best. We've got to move on now and work hard to bring in a replacement."
Cardiff have also completed striker Michael Chopra's club record £4m signing from Sunderland.
A statement on Charlton's website read: "The Bluebirds have paid an initial £1.075m for Hudson and will shell out a further £250,000 in the event of promotion to the Premier League. The deal also contains a sell-on clause."
Cardiff chairman Peter Ridsdale says they are also close to signing two more players who he refused to name, one of them thought to be Motherwell's Paul Quinn.
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