Strictly Come Dancing returned for its ninth series on 10 September 2011 with a launch show,^[1] with the live shows beginning on 30 September and 1 October 2011. The show was broadcast from Wembley Arena on 19 November with all proceeds going to the BBC charity, Children in Need.^[2] The finale took place in the Tower Ballroom at the Blackpool Tower and was the first episode to air in 3D. It was shown on BBC HD and in cinemas around the country.^[3]

This article needs additional citations for verification. (July 2011)

Sir Bruce Forsyth and Tess Daly continued to present the main show on BBC One, while the results show was presented by Daly and Claudia Winkleman. Former contestant Zoe Ball replaced Winkleman as the regular presenter of the spin-off show Strictly Come Dancing: It Takes Two due to Winkleman's family commitments.^[4] Alesha Dixon, Len Goodman, Craig Revel Horwood, and Bruno Tonioli returned as judges. On 5 and 6 November, Jennifer Grey, the winner of the eleventh series of Dancing with the Stars, served as a guest judge, replacing Len Goodman for the week.^[5] This was Alesha Dixon's last series as a judge after three years, which the BBC announced on 2 January 2012; she left the show to serve as a judge on a rival show, Britain's Got Talent.^[6]

One new professional dancer was added to the cast this series: Pasha Kovalev.

McFly drummer Harry Judd and Aliona Vilani were announced as the winners on 17 December, while Waterloo Road actress Chelsee Healey and Pasha Kovalev finished in second place, and actor Jason Donovan and Kristina Rihanoff finished in third.

The couples dance each week in a live show. The judges score each performance out of ten. The couples are then ranked according to the judges' scores and given points according to their rank, with the lowest scored couple receiving one point, and the highest scored couple receiving the most points (the maximum number of points available depends on the number of couples remaining in the competition). The public are also invited to vote for their favourite couples, and the couples are ranked again according to the number of votes they receive, again receiving points; the couple with the fewest votes receiving one point, and the couple with the most votes receiving the most points.

The points for judges' score and public vote are then added together, and the two couples with the fewest points are placed in the bottom two. If two couples have equal points, the points from the public vote are given precedence. As with the previous series, the bottom two couples have to perform a dance-off on the results show. Based on that performance alone, each judge then votes on which couple should stay and which couple should leave, with Len Goodman, as head judge, having the last and deciding vote.

This series featured fourteen celebrity contestants. The full lineup of celebrities was revealed on 6 September 2011 on The One Show.^[7] As in the previous series, the celebrities did not know who would be their professional partner until they were introduced to each other at the launch show.

The highest score each week is indicated in bold green with a dagger (†), while the lowest score each week is indicated in italicized red with a double-dagger (‡).

Color key:

Notes

Unless indicated otherwise, individual judges scores in the charts below (given in parentheses) are listed in this order from left to right: Craig Revel Horwood, Len Goodman, Alesha Dixon, Bruno Tonioli.

The couples performed the following each week:

• Week 1: One unlearned dance (cha-cha-cha or waltz)
• Week 2: One unlearned dance (foxtrot or salsa)
• Weeks 3–8: One unlearned dance
• Week 9: One unlearned dance & swing dance marathon
• Week 10: One unlearned dance
• Week 11: Two unlearned dances
• Week 12 (Show 1): Judges' choice & showdance
• Week 12 (Show 2): One unlearned dance & favourite dance of the series

Weekly ratings for each show on BBC One. All ratings are provided by BARB.^[9]