The fashion darling's loose fitting two-piece also featured glittering pinstripe which helped elongate her petite frame beside her towering co-stars.
The five-foot-five star - who plays the role of Nina Fawcett in the period movie - adorned her feet in a pair of head-turning mustard court heels as she made her way to the venue.
During a break in filming, the trio bought air pistols called BB guns and started ‘warfare’ – until producers told them off, Hoult reveals.
The 30-year-old - who is engaged to singer FKA Twigs - worked a pair of black denims which he teamed with a white shirt and kooky cropped wool turtleneck jumper.
Robert Pattinson and Mia Goth are working on a new movie together and it looks like they’re getting to know each other off-set as well!
In 2013, Dior Homme signed him as the face of their Fragrances.
In 2016, he also became the first brand ambassador of their Menswear collection. He sang songs for the Twilight film series and the 2008 independent comedy-drama film How to Be.
Leaving her golden locks loose, Sienna accentuated her flawless complexion with a dusting of blusher and a gloss covered lip.