Hudson, 34, and 35-year-old Bellamy opened up their Pacific Palisades home, which was decorated to look like a 'Game of Thrones' set, for the star-studded bash and dressed up like the characters from the fantasy series, reported Us magazine.
The actress' mother Goldie Hawn and her longtime partner Kurt Russell came dressed in traditional German attire.
Hollywood heartthrob Bradley Cooper arrived on a motorbike dressed as a gorilla, with his girlfriend Suki Waterhouse.
Also attending the party were new parents Fergie and Josh Duhamel, who dressed up as iconic Elvira from the 1988's horror movie, 'Elvira, Mistress of the Dark' and 'Rocky Horror Picture Show' character Riff Raff.