Click on photos for gallery of Sophie's party.
The elegant royal, a fan of the television show since she was a little girl, was in high spirits as she welcomed guests to the Buckingham Palace party.
Donning a scarlet dress with wavy feminine neckline, Sophie looked radiant as usual. The mother-of-two wore her hair swept up in a bun and completed her chic look with a matching diamond earrings and necklace set.
The beautiful royal chatted and laughed away with past and present Time Lords, including Matt Smith, Tom Baker, Peter Davison and John Hurt. Actresses Catherine Tate and Jenna-Louise Coleman, who have played the Doctor's companions, also attended the party and were pictured in deep conversation with the royal.
Sophie seemed to be enjoying being transported into the world of Doctor Who, as she walked around and admired the show's classic props.
The royal looked particularly entertained by the Doctor's arch nemesis, the feared Dalek, inspecting its plunge arms and heavily armoured exterior. Sophie seemed to take a special liking to Doctor Who's pet, K-9, and eagerly posed for a photo holding it, next to writer Stephen Moffat.
The party wouldn't be complete without the recognisable TARDIS and Sophie looked as if she was trying to jump in at one point.
The Buckingham Palace affair comes just a few days before Doctor Who reaches its 50th milestone on 23 November, when the BBC will screen a special episode titled The Day of the Doctor.
Sophie is not the only royal "Whovian" in the British royal family. Earlier this year, Prince Charles and Camilla, Duchess of Cornwall visited the Doctor Who studios at Roath Lock, Cardiff on their summer tour of Wales.
During the visit, the prince had cast members in fits of laughter as he impersonated a Dalek. Using a voice modulator, he uttered their famous catchphrase, "Exterminate", and revealed he had been a big fan of the BBC series since he was 15.