The 33-year-old stunner looked au naturale as she cuddled up to the Snapchat CEO.
'Happy Birthday to my love!!! I feel so incredibly blessed to have you as my partner,' Miranda captioned the picture.
The photo comes after the pair made a rare public outing at the Obama's Nordic state Dinner at the White House last month.
“We met at a dinner in LA for Louis Vuitton and became friends,' she told the Sydney Morning Herald. 'We were really good friends for a long time before we started dating. We've just been having fun together and sharing our time amongst friends and family.”