Premier League newcomers Cardiff City signed defender John Brayford from Derby County on Friday.
Malky Mackay's team had already agreed a fee for Brayford, believed to be around £1.5m, and the right-back has now put pen to paper on a four-year contract with the Bluebirds.
Brayford told Cardiff City's official website: "When I heard Cardiff were interested in signing me then I was obviously very interested, especially at the prospect of playing in the Premier League and testing myself at the highest level. Derby will always be a special club to me, but this was an opportunity I couldn't ignore."
Derby last month turned down a bid in the region of £1m from Wigan Athletic for the 25-year-old, but Cardiff's improved offer has persuaded the Championship club to cash in on a player whose contract was due to expire next year.
Brayford joined Derby from Crewe in 2010 and was player of the year in his first season with the Rams.