Liv, who has kept a low profile throughout her pregnancy until recently, cuddled up to Dave as they mingled with stars including Victoria and David Beckham – who is one of Dave's best friend.
Liv and Dave have been romantically linked since the summer
Armageddon actress Liv, who has a nine-year-old son called Milo from her marriage to British musician Royston Langdon, dressed her baby bump in a sheer black shirt with black and navy silk lining.
Liv and Dave were in stylish company at the event. Kate Moss, Alexa Chung and Victoria Beckham all showcased fashionable outfits at the magazine soirée.
Victoria chose a pair of ripped skinny jeans for the occasion, teaming them with a cropped cream swing top and an oversized black coat. The 40-year-old fashionista accessorised her outfit with a gold box clutch.
Dave is a close friend David Beckham
Supermodel Kate was joined by her husband Jamie Hince who spent the evening chatting to other invitees including her ex Jefferson Hack, Nick Grimshaw, Jamie Winstone and Bobby Gillespie.
The partygoers no doubt congratulated Liv and Dave on their future arrival. The couple, who have been dating since the summer, are said to be "madly in love" according to one source.
Having previously remained coy about her pregnancy, Liv thrilled her fans on Monday when she shared a photo of her blossoming baby bump on Instagram.