Ruby Sunday
Doctor Who character
Millie Gibson as Ruby Sunday
First appearance	"The Church on Ruby Road" (2023)
Created by	Russell T Davies
Portrayed by	Millie Gibson Amanda Walker (old)
Duration	2023–present
In-universe information
Species	Human
Affiliation	Fifteenth Doctor
Family	William Garnet (biological father) Louise Miller (biological mother) Carla Sunday (adoptive mother)
Relatives	Cherry Sunday (adoptive grandmother)
Home	Earth
Home era	21st century

Ruby Sunday is a fictional character in the British science fiction television series Doctor Who, created by Russell T Davies and portrayed by Millie Gibson. In the show's fourteenth series, starting with the Christmas special, Ruby serves as the companion to the Fifteenth Doctor (Ncuti Gatwa), an incarnation of the alien time traveller known as the Doctor.

Ruby Sunday is introduced in the 2023 Christmas special "The Church on Ruby Road". Ruby was born on Christmas Eve 2004. Her birth mother abandoned her on the outside of the titular Ruby Road church. She was then fostered and adopted by Carla Sunday (Michelle Greenidge). Nineteen years later, Ruby is trying to find information about her birth parents, to no avail. She is also experiencing unnatural bad luck, attracting the Fifteenth Doctor's interest. When Carla's new foster baby Lulubelle is kidnapped by human-eating goblins, Ruby boards their flying ship and formally meets the Doctor. After deducing that the goblins feed on coincidence and cause Ruby's bad luck, the Doctor and Ruby save Lulubelle. However, the creatures go back in time to kidnap Ruby on the day of her birth and eat her. The Doctor follows them and saves Ruby. Back in 2023, Ruby learns that the Doctor is a time traveller and follows him inside the TARDIS.^[1]

Ruby's first adventure, depicted in "Space Babies", shows the Doctor taking her to a space station housing a baby farm and a creature called the Bogeyman. On realising the Bogeyman was created for the children's entertainment, Ruby helps the Doctor save it from being ejected into space. The Doctor gives Ruby a TARDIS key and later attempts a DNA scan on her, to no avail. In "The Devil's Chord", Ruby requests to visit The Beatles in 1963, only to find that music has been erased due to the interference of Maestro (Jinkx Monsoon), a god of music. Ruby uses her musical skills in a failed attempt to bring music back into the world. Maestro discovers a "hidden song" within Ruby, before ultimately being defeated and music returning. In "Boom", Ruby attempts to help the Doctor after he steps on a landmine on a war-torn planet, only to be shot down by a soldier, mistaking her for a threat. After the Doctor reprograms a rogue Ambulance AI software, Ruby is healed.

In the episode "73 Yards", after the Doctor accidentally breaks a fairy circle and vanishes, Ruby is stalked by a figure who always appears 73 yards away and frightens off anyone that talks to her and makes them antagonistic towards Ruby, including Carla. After twenty years living alone, Ruby discovers the fairy circle made reference to future Prime Minister Roger ap Gwilliam (Aneurin Barnard), whom the Doctor had mentioned almost brought the world to nuclear war. Ruby uses the figure to frighten Gwilliam, who resigns in fear. Despite believing this would stop the figure stalking her, Ruby is proven wrong and lives the rest of her life continuously being stalked. A dying, elderly Ruby is approached by the figure, causing time to reset to the beginning of the episode. Ruby stops the Doctor breaking the fairy circle and the figure, revealed to be the older Ruby, vanishes.

In "Dot and Bubble", Ruby helps the Doctor rescue the people of Finetime from deadly slugs created by rogue Dots by communicating through their "bubbles", although the survivors refuse to travel with the Doctor out of prejudice, much to Ruby's disgust. In "Rogue", Ruby and the Doctor attend a party in 19th-century England. Ruby bonds with Emily (Camilla Aiko), one of the guests, as the party is invaded by Chuldurs, intending to "cosplay" as the human race. Ruby discovers Emily is a Chuldur and incapacitates her, impersonating her as the Chuldurs conduct a wedding ceremony. This leads to Ruby falling into a trap planted by the Doctor and bounty hunter Rogue (Jonathan Groff), intended to send the Chuldurs to an alternate dimension. Rogue pushes Ruby out of the trap as it activates, saving her and sending him to the alternate dimension.

Puzzled by the mystery of Ruby's birth mother and the mysteries surrounding her, including snow appearing at random intervals involving Ruby, the episode "The Legend of Ruby Sunday" shows the Doctor taking Ruby to UNIT HQ in an attempt to uncover her identity. Using a "Time Window" developed by the organisation, Ruby simulates the night her mother left her outside the church but is still unable to identify her. Ruby later witnesses the return of Sutekh, an ancient enemy of the Doctor's, and takes shelter in the Time Window. In "Empire of Death", Ruby uses the Time Window to create a "memory TARDIS", allowing her, the Doctor and Mel Bush (Bonnie Langford) to escape Sutekh as he destroys the universe. Deducing that Sutekh also wants to uncover the identity of Ruby's mother, the trio travel to 2046 to give Ruby a stronger DNA test. Sutekh kills and possesses Mel once the test is complete, demanding to know who Ruby's mother is. Controlling Mel, Sutekh returns the Doctor and Ruby to 2024, where they attach Sutekh to the TARDIS and drag him through the time vortex, undoing his destruction of the universe and destroying him. In the aftermath, UNIT identifies Ruby's birth mother as Louise Miller (Faye McKeever), a nurse who gave birth to Ruby when she was 15 and gave her away to protect her from her abusive stepfather. Ruby meets the 35-year-old Louise and introduces her to the Sunday family. The Doctor decides to leave Ruby with her family, promising to come back for her one day.

In January 2024, a Series 14 tie-in comic strip featuring Ruby Sunday with the Fifteenth Doctor was published in Doctor Who Magazine #599.^[2]

Auditions for the Fifteenth Doctor's companion took place on 24 September 2022.^[3] On 18 November 2022, during Children in Need, Millie Gibson was announced as the new companion Ruby Sunday.^[4]

In November 2023, it was reported that Gibson would stay for the fifteenth series and in January 2024, it was reported that Gibson would be leaving the show, to be replaced by Varada Sethu.^[5][6] The announcement led to the question of whether Gibson's tenure would make an impact with viewers.^[7][8][9] However, in April 2024 it was announced that Gibson and Sethu would appear concurrently throughout the series, with Davies stating that Ruby's character had been conceived around a two-series arc.^[10][11]

Gibson stated that series 15 would explore Ruby's life after travelling with the Doctor, which she described as unique to the series and "such a beautiful and clever thing to do".^[12]

Following her introduction, Ruby Sunday was positively received by critics. Empire's Jordan King praised the character's dynamics with Gatwa's Fifteenth Doctor and commented that "there's more than enough in Gibson's performance to suggest far greater depths yet for her to explore with the character."^[13] Ed Power from The Independent mentioned that Gibson's performance made her "immediately likeable", calling Ruby "a wonderful new companion".^[14]

Conversely, some reviewers were critical of Ruby’s characterisation, or the scripts; Asyia Iftikhar stating that she found it hard to connect with the Doctor and Ruby's releationship, feeling it "forced and shallow".^[15]

• Ruby Sunday on Tardis Wiki, the Doctor Who Wiki