Gorgeous supermodel Marisa Miller is expecting a baby boy, and she hasn't been afraid to show off her baby bump. The model and actress recently tweeted a photo of her growing baby bump on her birthday, in an underwater photo. "Thanks so much for all the sweet birthday wishes!" Miller wrote to fans. "Love you all! I had the best day and spent most of it underwater."

Miller, 34, announced in June that she and her husband, Griffin Guess, who were married in 2006, were expecting a child together. And in July, they happily announced that it would be a boy, and that Miller's due date was some time in December.

"We just found out that we are having a ... BOY!!! We would be excited either way, but it was amazing to know for sure," Miller told People Magazine.

"Griffin and I have spoken so much about having babies throughout our marriage. We already have enough names for three kids, haha!" said Miller, in a blog post for People. "It's always been a time we really looked forward to. I know you can't plan everything in life, but I knew that I wanted to really enjoy my pregnancy and have time to revel in motherhood as well."

But Miller, who is hailed in the industry for her toned, athletic body, admitted that although starting a family was a longtime dream for her and Guess, she postponed it due to the physical demands of her job. "My career is so focused on the physical that I really didn't want the pressure on or to have to worry about anything that happened to my body during that time," wrote Miller.

"There was so much freedom in letting go of my appearance because the reason for all these symptoms was this miracle growing inside me. I really could care less about what I looked like."

Miller's career -- she began modeling at 16 and appeared in the magazine Perfect 10 in 1997 -- didn't really begin to take off until 2001. That year she was discovered by famed photographer Mario Testino, and soon after began getting offers to do high profile jobs. At the time, however, she was still operating a surf school in Manhattan Beach, Calif.

Miller has since appeared on more than 80 magazine covers, including Sports Illustrated, Maxim, GQ, and FHM, who named her the Sexiest Woman in the World in their August 2010 issue. Miller is also set to appear in the film "R.I.P.D." with Ryan Reynolds and Mary-Louise Parker in 2013.

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Marisa Miller tweeted a very pregnant photo of herself on Aug. 6 with the caption, "Thanks so much for all the sweet birthday wishes! Love you all! I had the best day and spent most of it under water." Twitter
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Marisa Miller Reuters
U.S. model Marisa Miller attends a press event for the Sports Illustrated 2007 Swimsuit issue in Los Angeles
Marisa Miller, 26, from Santa Cruz, California, one of the models featured in the 2007 'Sports Illustrated' Swimsuit issue, poses at a press event in Los Angeles, California February 14, 2007. REUTERS
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Model Marisa Miller, who is in the final months of pregnancy, posed naked for a photo shoot for Allure. Reuters
2008 Cover Girl Marisa Miller
Supermodel Marisa Miller was the Sports Illustrated Swimsuit Edition cover girl in 2008. The 33-year-old model became a Victoria's Secret Angel in 2007. In 2008, she was ranked #1 on Maxim's "Hot 100" list, the same year she graced the Sports Illustrated Swimsuit Edition cover. Sports Illustrated
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A Victoria’s Secret Angel and an American actress, Marisa Miller who has been voted the seventh most sexy woman in the world, presents a $3 Million bra during the 2009 Victoria's Secret Fashion Show in New York November 19, 2009. REUTERS/Lucas Jackson
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Marisa Miller takes the stage to present an award at the 2010 ESPY Awards in Los Angeles Reuters
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Marisa Miller
Marisa Miller Twitter
Marisa Miller
Marisa Miller Reuters
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