Marisa Miller is no stranger to skimpy swimwear, and on August 6, the Sports Illustrated model showed off her pregnancy curves in a black bikini.
"Thanks so much for all the sweet birthday wishes! Love you all!" the 34-year-old wrote in a Twitter caption. "I had the best day and spent most of it underwater."
PHOTOS: Pregnant models
Miller and her husband, music producer and talent manager Griffin Guess, will welcome a baby boy in December. It will be the first child for both stars, who tied the knot on April 15, 2006.
PHOTOS: Supermodel moms
The former Victoria's Secret Angel -- who has graced more than 80 magazine covers in her career -- first tweeted a photo of her baby bump on Aug. 2.
"This was a month ago at 17 weeks. My belly seems to have doubled since!" Miller wrote. "Had to paddleboard to get to this cave."
VIDEO: Marisa Miller takes Us behind the scenes at Fashion Week
Miller next appears in the movie R.I.P.D., co-starring Ryan Reynolds, 35, and Jeff Bridges, 62. She is also the face of Harley Davidson.
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