But of course it's up to the expectant parents to decide when they want to make that big reveal!
Nick Lachey tweeted today that he and Vanessa are expecting their second child together, and that the baby will be a little sister for son Camden.
Vanessa unwittingly tipped off paparazzi about a month ago, however, when she was spotted shopping at Barney's New York in NYC and her belly under her T-shirt was just slightly rounder than usual.
And it was difficult to ignore, considering the 33-year-old TV host is preternaturally on the petite side.
Overall, in what turned out to be the most recent out-and-about sighting of her, Vanessa looked terrific in a casual jeans-and-T-and-varsity-jacket ensemble, her hair long and shiny (has someone been taking prenatal vitamins?) and her skin glowing.
"Don't put pressure on yourselves, moms! You just had a human being, and you're beautiful, and when it happens, it happens, and you get back in those jeans and it's awesome!" she said.
Our heartiest of congratulations to the happy family!