Rebecca Judd shares a photo of her rapidly growing bare baby bump.

Rebecca Judd is no pregnancy newbie. After all, she’s already mum to Oscar, almost 5, and Billie, 2. But she’s quickly learning that carrying twins is an entirely different ball game.

She’s taken to Instagram to share a photo of her rapidly growing baby belly and how she’s dealing with her quickly growing ‘mummy tummy’.

Rebecca Judd talks to Holly Wainwright about walking the Myer fashion show while breastfeeding:

“19 weeks with twins- feeling the same size as around the 26 week mark with my singleton pregnancies,” her caption read. “This mummy tummy is going to get HUGE.”

Rebecca recently spoke to to Kate Waterhouse after she was forced to refute claims that she regularly skips meals to maintain her slim figure.

“I don’t try to look this way,” she told Date With Kate. “I just do.” “‘Believe me,” she added. “Nobody has the energy to grow four big, bouncing babies, work a gazillion jobs, run businesses, a household and a family on an empty stomach.”

  Amazing new fringed boots by @biancabuccheri at @dolcifirmeshoes (I know I should be working ????)   A photo posted by Rebecca Judd (@becjudd) on May 10, 2016 at 5:45pm PDT

Rebecca previously revealed she is expecting identical twin boys with husband Chris. She has said the news of twins had taken the parents greatly by surprise, saying she and her husband had been “happily going through life thinking there’s just a singleton in there.”

Check up Rebecca Judd’s gorgeous Melbourne home…