Amanda Seyfried announced that she's expecting her first child with fiance Thomas Sadoski on Tuesday, while attending the Givenchy press launch for their new Live Irresistible fragrance.

Seyfried -- who's a spokesperson for the brand -- showed off her tiny baby bump in a gorgeous sheer black mini dress.

Tyron Machhausen, Amanda's makeup artist, likewise shared photo from the event on Instagram (above). "Congratulations to the insanely gorgeous #AmandaSeyfried - What a beautiful Mama! Attending tonight's #Givenchy event," he captioned the photo.

People first announced the news.

1130_amanda_insestLaunch GalleryGettyHollywood's Hottest Celebrity Couples

Reports started surfacing back in September that the 30-year-old "Mean Girls" star and Sadoski were engaged, when she was spotted with a simple silver ring on that finger.

The cute couple first met last year while starring on the off-Broadway show, "The Way We Get By" together.

Are you surprised by the "Mamma Mia!" star's big baby news? Tell toofab in the comment section below and check out the gallery above to see more expecting stars!

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