Fancy nude portraits are practically a rite of passage for pregnant models, particularly as bared baby bumps are usually a hit on newsstands. And with three Victoria's Secret models currently with child, editors are probably licking their chops to get those bellies on their pages. Interestingly, Alessandra Ambrosio made her first foray into "the Demi Moore" not for a magazine but for an ad for Vivara jewelry, shot by Mert Alas and Marcus Piggott. (Ambrosio posted the photos to her Facebook page over the weekend.) During Ambrosio's first pregnancy in 2008, she apparently got lots of cover offers but said she turned them all down because she wanted to relax at home in Brazil. Perhaps things are different this time around — or perhaps Vivara just offered her lots and lots of money. Either way, it's a beautiful picture.