Every Doctor Who companion to leave after one season

Doctor Who is almost as synonymous with The Doctor as it is with the character's companions, but they have not always stayed on for long.

It was previously reported by Variety that Millie Gibson, who joined Doctor Who as Ruby Sunday in its 2023 Christmas Special, would only play the role for one season and would be replaced by Varada Sethu. However this has now been confirmed not to be the case. Instead, the BBC has announced that Sethu is joining the show to be a companion alongside Gibson's Ruby.

Read more: When does Doctor Who series 14 start on TV?

The idea of changing a companion early on is not a surprising one for the BBC series, though, as it has been the case in both the classic and modern era previously. Here is everything you need to know.

Every Doctor Who companion to leave after one season

Katarina

Adrienne Hill portrayed Katarina in season three of the Classic Who era, and is one of the most short-lived of the Doctor's companions as the character was killed off after just five episodes, the first to be written off the show in this way. Katarina was a Torjan handmaiden who joined William Hartnell's First Doctor for The Myth Makers and The Daleks' Master Plan.

Dodo Chaplet

Jackie Lane starred as Dodo Chaplet in season three of Classic Who, starring alongside William Hartnell's First Doctor from February to July 1966. The teen came into the Doctor's life when she walked into the TARDIS thinking that it is a real police box.

Read more: Doctor Who: The 60 best stories

Dodo appeared in 19 episodes, some of which have since been lost, and was later replaced by Polly (Anneke Wills) and Ben (Michael Craze) on the show.

Liz Shaw

Caroline John took on the role of Liz Shaw in season seven of Classic Who, starring as the companion of Jon Pertwee's Third Doctor. The character was a civilian member of UNIT who met the Doctor during the events of 1970 episode Spearheads from Space.

The character, who graduated from Cambridge, was a scientist with degrees in medicine, physics and other subjects which she had obtained before joining the Doctor on his adventures. The character appeared in 25 episodes of the show, and though she was not given a farewell scene as such Liz continued to be mentioned and was known to continue working with UNIT after her time with the Doctor.

Martha Jones

Freema Agyeman was introduced as Martha Jones in season 3 following the departure of Billie Piper from the series, appearing in the episode Smith and Jones where she helps save the day when the hospital she works in is transported to the moon. After helping the Tenth Doctor (David Tennant), the Time Lord offers her the chance to travel with him across time and space.

Read more: Doctor Who's biggest season 14 mysteries from Mrs Flood to Ruby's mother

Her final regular appearance came in the episode Last of the Time Lords, in which she saved the Doctor by reversing time after the Master (John Simm) took over Earth. Though the Master's actions were undone, Martha retained her memories of his actions and thus chose to leave the TARDIS and forge her own path.

Though she only appeared in one season of the show, Agyeman reprised her role as Martha in guest appearances in season 4 and the special The End of Time. She also made a cameo appearance in BBC spin-off Torchwood.

Donna Noble

Catherine Tate quickly became one of the most beloved Doctor Who companions when she was introduced as one in series four, following her appearance in the 2006 Christmas special The Runaway Bride. So it's hard to forget that she only had a regular starring role for one season.

The character joined the Tenth Doctor for the duration of season four, which culminated in the Time Lord erasing Donna's memories of him after she is absorbs all of the Doctor's knowledge, something her brain is not able to process.

The character returned for the two-part special The End of Time which saw Tennant's Doctor regenerate into the Eleventh Doctor (Matt Smith). Donna then made her comeback in the 60th anniversary specials, with Tate and Tennant returning, which saw the character's memory be restored safely.

Donna and the Fourteenth Doctor went on three new adventures together — titled The Star Beast, Wild Blue Yonder and The Giggle — before helping to welcome Gatwa's Fifteenth Doctor to the franchise.

Bill Potts

Bill Potts (Pearl Mackie) was introduced as a companion for Peter Capaldi's Twelfth Doctor, and she was introduced to the character in season 10 when the Doctor decides to take her under his wing after realising her untapped potential as a time-travelling companion.

The character was the first openly gay companion to appear on the BBC series, and her adventures with the Doctor culminated in a shocking moment in the show's two-part finale where she was shot and in the ten years in took the Time Lord to reach her she was converted into a Cyberman though she retains her emotions and memories.

When the Cybermen are defeated, and the Doctor appears to have died, Bill is saved by her girlfriend Heather (Stephanie Hyam) who offers to make her an alien creature like herself or return to Earth. Bill agrees to the former, and they go on their own adventures in time and space. Bill made her final appearance on the series in the Christmas special Twice Upon a Time, where she appeared as an avatar created from Bill's memories that were stored at the time of her death in season 10.

Nardole

Nardole (Matt Lucas) was introduced as the Doctor's assistant in season 10, after appearing as the Time Lord's companion in the 2016 Christmas special The Return of Doctor Mysterio. The character appeared alongside Bill in season 10, though Nardole often preferred staying safe on Earth than travelling across time and space.

Dan Lewis

Jodie Whittaker's time as The Doctor saw the Time Lord have a family rather than classic companions, as she initially went on adventures with Graham (Bradley Walsh), Ryan (Tosin Cole), and Yasmin (Mandip Gill). After the departure of the first two, Yaz and the Doctor were joined by John Bishop's Dan Lewis.

Read more: Doctor Who: Will David Tennant return?

Dan appeared in season 13, also known as Flux, and joined the Doctor after being captured by Karvanista during the events of the episode. The character made a cameo appearance in Whittaker's final special: The Power of the Doctor.

Doctor Who series 14 returns on Saturday 11 May on BBC One, BBC iPlayer and Disney+.

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