12/27/2012 at 04:00 PM EST
and proud to show it.
The expectant star – who is vacationing in Hawaii with her fiancé Eric Johnson, their 7-month-old daughter Maxwell Drew
and other family members – posted a revealing photo of herself smiling and clearly enjoying the laid back lifestyle of the islands on Thursday.
"Fun in the sun," Simpson, 32, wrote to accompany the Twitpic
, which shows the star wearing her sun-kissed blonde hair loose and dressed in a red beach frock and a cowboy hat.
Simpson hasn't been shy about sharing her happiness on Twitter over the holidays. On Christmas Day, she revealed the news of her pregnancy by sharing a picture of her daughter with the words "Big Sis" written in the sand in front of her. And on Wednesday, Simpson posted a shot
of herself grinning with Johnson on the beach.