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  • Writer's pictureAlexandra (Alex) P.

DOCTOR WHO 101: Understanding the Basics of ‘DOCTOR WHO’

Updated: May 9

Doctor Who is a science-fiction television show that follows The Doctor, a Time Lord who seeks to end catastrophic events after running away in a blue box to save the universe. While traveling the universe, The Doctor has the help of his companion (or companions, depending on the era in question) to assist him with helping people in need across the galaxy.


The Doctor is an over one thousand year-old time traveling alien with a brilliant mind, or minds, from the planet of Gallifrey. The Doctor turned his guilt of witnessing the death of the Time Lords (his alien race) during the Time War as a catalyst to help the oppressed. 

From top to bottom, left to right: Ninth Doctor (Christopher Eccleston), Tenth Doctor (David Tennant), Eleventh Doctor (Matt Smith), Twelfth Doctor (Peter Capaldi), Thirteenth Doctor (Jodie Whittaker), Fifteenth Doctor (Ncuti Gatwa). ©BBC

The lore of the Doctor spans over 60 years with 15 different Doctor incarnations. The first Doctor, played by William Hartnell, established the stepping stones for the character in 1963. The original seasons of Doctor Who ran from then to 1989 before the establishment of modern-day Doctor Who with Christopher Eccleston’s ninth Doctor. Other actors who follow in suit to Eccleston include David Tennant, Matt Smith, Peter Capaldi, Jodie Whittaker and Ncuti Gatwa. 

The Eleventh Doctor, played by Matt Smith, regenerating. © BBC

In order for different Doctor incarnations to arise, the Doctor has to go through a stage called regeneration. Regeneration is the physical and physiological change of the Doctor’s body typically caused by an immense amount of stress on his physique. This provides the room for a new actor to step in the Doctor’s shoes typically for a few seasons.

David Tennant's Fourteenth Doctor regenerates to Ncuti Gatwa's Fifteenth Doctor during the first bi-regeneration. © BBC and Disney

The current actor to take on the role of the Doctor is Ncuti Gatwa. Gatwa’s 15th Doctor follows Tennant’s 14th after the first occurrence of a bi-regeneration (that’s another story for another day if you’re new to the Who world). Ncuti Gatwa’s era of Doctor Who marks the start of a new era for the series made for new and returning viewers alike.


The Doctor needs a mode of transportation to travel across the galaxy, and time; here enters the TARDIS.


The TARDIS (which stands for Time and Relative Dimension in Space) is a spaceship from the planet of Gallifrey stolen by the Doctor. It’s notorious for its British 1950s phone box design with an interior suitable for living since it’s “bigger on the inside”. The TARDIS’ interior often changes its design along with the Doctor’s reincarnation with more to offer each time. 

While the TARDIS’ main function is to act as a spaceship for the Doctor and Co., it has a number of other functions as well. The TARDIS comes with numerous circuits to assist the Doctor and his companions including a Chameleon circuit that changes the exterior of the TARDIS to blend in with its surroundings (that's currently broken in canon), a Telepathic circuit implemented to send messages to both the Doctor and other people, and a Translation circuit that gets into a TARDIS passenger’s brain to translate any language to their native tongue, just to name a few. 


The Doctor typically doesn’t travel alone ─ people who tag along with him are called companions. There isn’t a specific requirement to become a companion besides for traveling with the Doctor. Their stories act as a second narrative in the show with as much complexity as the lead story. These stories can drive the narrative of the season and support the Doctor's actions as well. Most companions stay with the Doctor for a few seasons before leaving the show. Some companions have even returned later to help more people across the galaxy.

From top to bottom, left to right: Rose Tyler, Martha Jones, Donna Noble, Amy Pond, Rory Williams, Clara Oswald, Bill Potts, Yasmin Khan © BBC

The newest companion in the world of Who is Ruby Sunday (Millie Gibson), who first met Ncuti Gatwa’s Fifteenth Doctor in The Church on Ruby Road. Previous companions of the modern era include Rose Tyler, Martha Jones, Donna Noble, Amy Pond, Rory Williams, Clara Oswald, Bill Potts, and Yasmin Khan to name a few. 

Millie Gibson as Ruby Sunday (top left), Yasmin Finney as Rose Noble (top right), Ncuti Gatwa (center) with Millie Gibson (left) and Varada Sethu (right) on the set of Doctor Who Season 2. © BBC

Gatwa’s Fifteenth Doctor already has a few companions joining his cosmic joyride. Along with Millie Gibson’s Ruby Sunday, Yasmin Finney’s Rose Noble (Donna Noble’s daughter) is expected to make an appearance in Season 1. Varada Sethu will join Gatwa and Gibson in Doctor Who season two, now in production for Disney Plus set for a release in 2025. 


If you're new to Doctor Who and want to tune into Ncuti Gatwa's first season as it's airing, don't worry about trying to get caught up on prior seasons before May 10. While you should watch the other seasons eventually, this new era was formulated to be welcoming to new viewers. I recommend watching The Church on Ruby Road to see the first adventure of the Fifteenth Doctor with Ruby Sunday on Disney Plus in the meantime.

Ncuti Gatwa and Millie Gibson as the Fifteenth Doctor and Ruby Sunday in Doctor Who: The Church on Ruby Road, now streaming on Disney Plus. © BBC and Disney

All episodes of modern-day Doctor Who (Doctor incarnations from Eccleston to Whittaker) are available on Max. If you want to see content from David Tennant’s Fourteenth Doctor, head over to Disney Plus to watch Doctor Who: The Star Beast, Doctor Who: Wild Blue Yonder, and Doctor Who: The Giggle.

Left-Right: Christopher Eccleston, David Tennant, Jodie Whittaker, Matt Smith and Peter Capaldi as The Doctor. © BBC
David Tennant as the Fourteenth Doctor. © BBC and Disney

Season One of Doctor Who’s new era, starring Ncuti Gatwa and Millie Gibson, premieres with two episodes on May 10th at 7PM ET/4PM PT in the US and worldwide (minus Ireland and the UK) on Disney Plus and May 11 at 12AM GMT in Ireland and the UK on BBC iPlayer.


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