The 32-year-old British celebrity posted a Polaroid of herself holding her child, who was covered in a heart-shaped blanket.
At a festival in Mexico last November, Waterhouse made her pregnancy public for the first time on stage.
She hinted at her developing baby belly when she informed concertgoers she had deliberately decided to wear something glittery to “distract” from “something else”.
Later on, she shared a number of photos from the show, one of which showed off her baby bulge.
It’s thought that Waterhouse and Pattinson, 37, have been dating intermittently since 2018.
The actor became well-known for his role as Edward Cullen in the Twilight trilogy movies.
