“GLOW BABY GLOW!!! #anydaynow,” the Las Vegas alum, 43, captioned the image of her bare burgeoning belly.
Last week, Sims shared a snapshot holding daughter Scarlett, 21 months, while 4-year-old son Brooks kissed her bare baby bump.
The model-actress and her husband, movie producer Scott Stuber, are expecting a son this time around.
In August, Sims announced her third pregnancy.
We can’t wait to hear their exciting news!