Stylist Lana Wilkinson posted a BTS look at the star on set, showing off a number of looks, but not giving the project away.
Bec also posted a number of photos to Instagram of her beauty looks from the shoot.
“Shooting a dream career campaign today- can't wait to share with you what I'm up to. Hint.... It's all about skin + face,” she wrote.
The TV presenter, who is already a mum to four-year-old son Oscar and two-year-old daughter Billie, revealed just last week that she is at 19 weeks along in her pregnancy.
“19 weeks with twins - feeling the same size as around the 26 week mark with my singleton pregnancies. This mummy tummy is going to get HUGE.”