Strictly Come Dancing returned for its nineteenth series with a launch show on 18 September 2021 on BBC One, and the live shows beginning on 25 September.^[1] Tess Daly and Claudia Winkleman returned as hosts, while Rylan Clark-Neal returned to host Strictly: It Takes Two alongside new presenter Janette Manrara, who replaced Zoe Ball.^[2] In June 2021, the BBC announced that Shirley Ballas, Motsi Mabuse, and Craig Revel Horwood would return to the judging panel. Anton Du Beke, who served as a guest judge in the previous series, joined the panel in place of Bruno Tonioli, who did not return for the second year in a row due to travel restrictions imposed by the COVID-19 pandemic.^[3][4]

In July 2021, the show's executive producer, Sarah James, said the show would return for a "full-length series", with fifteen celebrities, themed weeks, pre-recorded professional group dances, and a Christmas special, but no Blackpool Tower Ballroom special.^[5] For this series, the contestants were no longer restricted to perform one of the "couple's choice" categories — contemporary, theatre/jazz, or street/commercial — and could instead incorporate the routine however they wished.^[6] In September, a row broke out over whether dancers should be vaccinated against COVID-19. Reports had suggested that three dancers had refused to be vaccinated, with one unnamed celebrity already having to self-isolate since the show's launch night had been filmed.^[7]

EastEnders actress Rose Ayling-Ellis and Giovanni Pernice were announced as the winners on 18 December,^[8] while John Whaite and Johannes Radebe — the first male same-sex couple to compete on the programme — finished in second place.

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 Shirley Ballas, as head judge, having the last and deciding vote.

In March 2021, the BBC announced that all sixteen professional dancers from the eighteenth series would return in 2021.^[9] However, in June, the BBC revealed that Janette Manrara and Anton Du Beke would not be reprising their dancing roles: Manrara was announced as a new co-host of It Takes Two, succeeding Zoe Ball, while Du Beke would replace Bruno Tonioli on the judging panel.^[2][4]

In July 2021, the BBC announced that four new professional dancers would be joining the cast: Italian Latin and Ballroom Champion Nikita Kuzmin, who was also a professional dancer on the German version of the show in 2020; South African Latin Champion Cameron Lombard, who was also a finalist on South Africa's Got Talent in 2012; Polish Open Latin Champion Jowita Przystał, who won The Greatest Dancer in 2020; and World Junior Latin American Champion Kai Widdrington, who was also a former professional on the Irish version of Dancing with the Stars.^[10]

Graziano Di Prima received a celebrity partner for the first time since the sixteenth series, while Nadiya Bychkova and Neil Jones received a celebrity partner for the first time since the seventeenth series. Nancy Xu received a celebrity partner for the first time, as did Nikita Kuzmin and Kai Widdrington, while Luba Mushtuk, Cameron Lombard, and Jowita Przystał did not receive a partner.^[11][12]

This series featured fifteen celebrity contestants. On 4 August 2021, the first three celebrities participating were announced: Tom Fletcher, AJ Odudu, and Robert Webb.^[13] The following day, it was announced that John Whaite would be paired as part of the first male same-sex couple in Strictly Come Dancing history.^[14] Celebrity contestants continued to be revealed until 13 August 2021, when the full line-up was announced.^[11] Rose Ayling-Ellis was also the first deaf contestant to appear on the programme.^[15] On 13 October, it was announced that Robert Webb had been advised to withdraw from the competition due to health problems.^[16] On 17 December, the day before the final, it was announced that AJ Odudu had withdrawn from the competition after suffering ligament damage in her right ankle.^[17]

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, Motsi Mabuse, Shirley Ballas, Anton Du Beke.

The couples performed the following each week:

• Weeks 1–11: One unlearned dance
• Week 12 (Semi-final): Two unlearned dances
• Week 13 (Final): Judges' choice, favourite dance & showdance

Series 19 received positive reviews from fans and critics. Lottie Townend of Glasgow University Guardian said that "the series provided a place of escape and comfort from the difficulties of the outside world. You become personally invested in each contestant’s journey, root for their success and feel the warmth through their shared love for dance".^[62] Jane Rackham of Radio Times was positive towards this season's unpredictability, writing: "This must be the most unpredictable series of Strictly ever. And not only because several participants had to miss a show after testing positive for Covid".^[63]

Weekly ratings for each show on BBC One. All ratings are provided by BARB.^[64]