Kate walked the red carpet in a flowing forest green empire waist Jenny Packham gown with a long train and black sash, paired with black suede wavy cutout Prada heels, diamond and emerald earrings and a matching necklace and a black clutch. William wore a black tux.
Celebrity attendees included Angelina Jolie, Jennifer Lawrence, Game of Thrones alum Natalie Dormer, Chiwetel Ejiofor, Naomie Harris, Salma Hayek and Sir Patrick Stewart.
Protesters crashed the red carpet to demonstrate against British Prime Minister Theresa May's domestic violence policies, but quickly left after police intervened. They did not make contact with any stars and no arrests were made.
Nominated stars for the 2018 BAFTAs include Three Billboards Outside Ebbing, Missouri's Frances McDormand, I, Tonya's Margot Robbie, Lady Bird's Saoirse Ronan, Get Out's Daniel Kaluuya, Phantom Thread's Daniel Day-Lewis and Call Me by Your Name's Timothée Chalamet.