The couple, who have been an item for seven years, posed together as they attended the release party for Eric Schmidt and Jonathan Rosenberg's new book, How Google Works, at the Chiltern Firehouse.
Beatrice and Dave have been dating for over seven years
Beatrice, 26, and Dave, 31, were joined at the trendy London restaurant by Jemima Khan, Arpad Busson and Nick Candy.
Prince Andrew's eldest daughter opted to wear a chic black ensemble for the evening, teaming a knee-length dress with sheer panelling and a white collar with a silk-lined blazer, tights and heels.
The University of London graduate added a pop of colour to her outfit with a mulberry-hued clutch bag.
Dave, who works for Richard Branson's company Virgin Galactic, looked dapper in a navy blue suit.
Also present at the book launch were Lord Edward Spencer-Churchill, American film producer JJ Abrams, Made in Chelsea star Emma Miller, financier Nat Rothschild, entrepeneur Marissa Montgomery and Salman Rushdie's son Zafar.