The former Mis-Teeq star will not rejoin colleagues Len Goodman, Craig Revel Horwood and Bruno Tonioli when the BBC competition returns later this year.
On her official website, Dixon commented: ''After three incredible years on the Strictly Come Dancing judging panel I have decided that it is time to move on. 'Strictly Come Dancing will always hold a special place in my heart as it has been such an amazing experience, both as a winning competitor and as a judge.
''I would like to say a big thank you to everyone involved in the show, the production team, my fellow judges, and a very special thank you to the fans for their support.''
A BBC spokesperson added: "We wish her all the best. She has done three very successful series with us and we look forward to announcing our new lineup in due course."
Dixon competed in the 2007 series of the dancing competition, which she won alongside partner Matthew Cutler. She was apppointed to the judging panel in 2009, replacing axed judge Arlene Phillips.
The controversial decision to replace the choreographer was met with heavy criticism by some viewers. However, the BBC stood by Dixon, while Phillips herself has said that she has "come to accept" her exit.
Dixon released her third solo album The Entertainer in 2010. The album, which included singles 'Drummer Boy' and 'Radio', peaked at number 84 in the UK album chart.
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Watch Alesha Dixon's new Weight Watchers advert below: