Featuring a seductive Bardot neckline, the Duchess' Alexander McQueen dress was tailored to emphasise her tiny waist before flaring out into a tiered skirt.
The royal couple stole the show in their sophisticated looks as Kate coordinated with Prince William, 34, in his dapper black suit and bow-tie.
Duchess of Cambridge Kate Middleton looked incredible in on the BAFTAs red carpet
Kate and Prince William on the red carpet at the Royal Albert Hall
Kate wore a stunning Alexander McQueen gown
BAFTAs 2017: Best and worst dressed
Sun, February 12, 2017
BAFTAs 2017: The best and worst dressed from star-studded red carpet at the Royal Albert Hall.
1 of 54
BAFTAs 2017 in pictures
Get Quotes on Home Insurance
Kate beamed on the BAFTAs red carpet, her luscious brunette locks coiffed into a classy up-do, revealing huge teardrop diamond earrings.
She opted for sultry black eye make-up in a cats-eye style and a nude lipstick to compliment her subtle blush as the couple braved the bitter cold of London.
Reports had suggested that BAFTA bosses were concerned about the Duchess attending tonight's event for fear she might overshadow the A-list celebrities.
The Duchess opted for a Bardot neckline showing off her décolletage
William has been the president of the British Academy of Film and Television Arts since 2010 and is due to present the Fellowship Award on stage tonight alongside his wife.
Emma Stone and Ryan Gosling's smash hit La La Land heads up the awards with an incredible 11 nominations, including Leading Actress and Actor, Director and the coveted Best Film gong.
Stephen Fry is set to host tonight's 70th Annual BAFTA Awards at the Royal Albert Hall, making it his 12th time at the helm for the show.