Katy, 34, posed with her fiancé Orlando, 42, in a light pink gown that featured silver chains and rocked a sleek blonde bob.
The actor, who stars in the series, looked dapper in a navy blue suit and shiny black dress shoes.
Cara, 27, who is also starring in Carnival Row made jaws drop in multi-colored gown and a pair of black platform heels.
The supermodel rocked a bold purple eyeshadow and kept her blonde locks pulled back into a sleek ponytail.
Cara's girlfriend Ashley Benson also made an appearance to support her partner! Ashley, 29, looked great in a black mini dress and a matching blazer with black heels.
Whose outfit do you like best? Let us know in the comments below!