Lucy, 22, kept it effortlessly chic in London's Leicester Square by wearing a sequinned two-toned sleeveless tunic, which she teamed with pair of sexy black trousers.
The reality star carried a shiny silver clutch and rocked a strappy pair of black heels from high street store Dune.
Although her outfit was based on a black and grey theme, Lucy wore a bright pink crystal ring to add a pop of colour.
Finally, Lucy added some oomph to her long hair at the roots and topped off her look with metallic eyes and a glossy lip.
Lucy joined fellow celebrities The Saturdays at the We're The Millers premiere and, just like Mollie King, was left starstruck by the gorgeous sight of the film's leading lady - Jennifer Aniston.
"At the We're The Millers premiere! Why is Jennifer Aniston so amazing?" Lucy asked her fans.
One of life's great mysteries, Luce!
We're The Millers hits cinemas on 23 August.
Watch a trailer for We're The Millers below:
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