A Centenary Special is a Special episode of Doctor Who that is extremely rare, as they would celebrate the 100th Anniversary of its subject.
As part of the BBC 100 celebrations, celebrating the 100th anniversary of the British Broadcasting Corporation on 18 October 2022, a Centenary Special was written by then-showrunner Chris Chibnall to feature along with other shows airing as part of the event. The episode aired on 23 October 2022.
Other candidates
The Stones of Blood, broadcast between 28 October and 18 November 1978, happened to be the one-hundredth televised Doctor Who story. To commemorate this, Anthony Read asked David Fisher to write a new scene (expanded by Darrol Blake) featuring Romana and K9 surprising the Fourth Doctor with a birthday cake (and a new identical scarf), celebrating his seven hundred fifty-first birthday. However, producer Graham Williams vetoed this idea as being too self-indulgent and the scene was never shot. Blake had already ordered a cake, and this was eaten by the cast and crew.
Broadcast on 24 October 2015, The Woman Who Lived was the 100th story of the "New Who" era.