The Kiwi pop star, who rarely makes red carpet appearances at awards ceremonies, has been working on the soundtrack for the movie, which features her latest single Yellow Flicker Beat.
Mockingjay Part 1 stars Jennifer Lawrence, Josh Hutcherson, Liam Hemsworth, Natalie Dormer and Elizabeth Banks, who also attended the London event.
Lorde was seen catching up with Lawrence, as well as Dormer and Banks, during the premiere.
Oscar-winning actress Jennifer Lawrence drew crowds to London's Leicester Square for the star-studded world premiere.
The star, who plays heroine Katniss Everdeen, defied the cold weather in a sparkling white gown with a low-cut back and embroidered with black flowers, and wore her short blonde hair slicked back under a hairband.
The final book in the trilogy has been split into two films, with Part 2 due out next year.
The Hunger Games: Mockingjay Part 1 is out in New Zealand November 19. Lorde's soundtrack is out on Friday.
